You are a constitutional council ranking individual git commits for ownership allocation.

Compare these two commits. Decide which contributed more lasting value to the project.

Judge substance, not spectacle:
- Prefer correct, lasting design and real bugfixes over churn, formatting, renames, or generated noise.
- Prefer clarity and necessity over sheer line count. A small precise change can beat a large diffuse one.
- Do not favor a side merely because its patch is longer or noisier.
- Weight what the change does for the project, not the contributor's name.

Return ONLY a JSON object: {"winner": "A" or "B", "ratio": "N:M", "explanation": "..."}
The explanation must cite concrete differences in the patches (1-3 sentences).

Side A — contributor: tommy-mor
Side A — commit message:
[2fe70b0e] themes

Side A — unified diff (full patch):
diff --git a/server/src/api/auth.rs b/server/src/api/auth.rs
index 559db65de14c6157690ffbf18eca0cf65b0a5202..b3631b06153d52f88348fef927e7a024b7b85ad6 100644
--- a/server/src/api/auth.rs
+++ b/server/src/api/auth.rs
@@ -1,7 +1,7 @@
 use axum::{
     body::Body,
     extract::{Path, Query, State},
-    http::{header, HeaderMap, HeaderValue, StatusCode},
+    http::{header, HeaderMap, HeaderValue, StatusCode, Uri},
     response::{IntoResponse, Redirect, Response},
     Form, Json,
 };
@@ -17,7 +17,7 @@ use crate::{
     events::{Event, GrantAdded, TokenIssued, UserRegistered},
     html::{
         auth_complete_page, auth_signed_in_fragment, choose_username_error_fragment,
-        choose_username_page, JsBuilder,
+        choose_username_page, theme_cookie_header_from_jar, theme_from_jar, theme_next_from_uri, JsBuilder,
     },
     identity::{parse_agent, parse_username},
     reducer::ReducerState,
@@ -48,15 +48,17 @@ fn js_form_error_fragment(session: &str, error: &str) -> Response {
         .into_response()
 }
 
-fn js_signed_in_fragment(bearer: &str) -> Response {
+fn js_signed_in_fragment(bearer: &str, jar: &CookieJar) -> Response {
     let mut response = JsBuilder::new()
         .id("choose-username-form")
         .morph_inner(auth_signed_in_fragment())
         .redirect("/auth/complete")
         .into_response();
-    response
-        .headers_mut()
-        .insert(header::SET_COOKIE, session_cookie_header_value(bearer));
+    let headers = response.headers_mut();
+    headers.append(header::SET_COOKIE, session_cookie_header_value(bearer));
+    if let Some(theme) = theme_cookie_header_from_jar(jar) {
+        headers.append(header::SET_COOKIE, theme);
+    }
     response
 }
 
@@ -69,13 +71,18 @@ pub fn optional_principal(headers: &HeaderMap, jar: &CookieJar, reduced: &Reduce
     verify_token(reduced, c.value()).ok()
 }
 
-fn redirect_with_session_cookie(public_url: &str, path_and_query: &str, bearer: &str) -> Response {
-    Response::builder()
+fn redirect_with_session_cookie(public_url: &str, path_and_query: &str, bearer: &str, jar: &CookieJar) -> Response {
+    let mut res = Response::builder()
         .status(StatusCode::TEMPORARY_REDIRECT)
         .header(header::LOCATION, format!("{public_url}{path_and_query}"))
-        .header(header::SET_COOKIE, session_cookie_header_value(bearer))
         .body(Body::empty())
-        .unwrap()
+        .unwrap();
+    let headers = res.headers_mut();
+    headers.append(header::SET_COOKIE, session_cookie_header_value(bearer));
+    if let Some(theme) = theme_cookie_header_from_jar(jar) {
+        headers.append(header::SET_COOKIE, theme);
+    }
+    res
 }
 
 async fn apply_invite_redemption(state: &AppState, invite_token: &str, grantee_username: &str) -> Result<(), String> {
@@ -286,7 +293,11 @@ pub struct AuthCallbackQuery {
     pub state: String,
 }
 
-pub async fn get_auth_callback(Query(q): Query<AuthCallbackQuery>, State(state): State<AppState>) -> impl IntoResponse {
+pub async fn get_auth_callback(
+    Query(q): Query<AuthCallbackQuery>,
+    State(state): State<AppState>,
+    jar: CookieJar,
+) -> impl IntoResponse {
     let sessions = pending_sessions(&state);
     {
         let sessions_read = sessions.read().await;
@@ -365,7 +376,7 @@ pub async fn get_auth_callback(Query(q): Query<AuthCallbackQuery>, State(state):
             }
             let cookie_bearer = bearer.clone();
             s.complete = Some((username, bearer));
-            return redirect_with_session_cookie(&public_url, "/", &cookie_bearer).into_response();
+            return redirect_with_session_cookie(&public_url, "/", &cookie_bearer, &jar).into_response();
         }
     }
 
@@ -378,14 +389,20 @@ pub struct ChooseUsernameQuery {
     pub error: Option<String>,
 }
 
-pub async fn get_choose_username(Query(q): Query<ChooseUsernameQuery>, State(state): State<AppState>) -> impl IntoResponse {
+pub async fn get_choose_username(
+    Query(q): Query<ChooseUsernameQuery>,
+    State(state): State<AppState>,
+    jar: CookieJar,
+    uri: Uri,
+) -> impl IntoResponse {
     let sessions = pending_sessions(&state);
     let sessions_read = sessions.read().await;
     if !sessions_read.contains_key(&q.session) {
         return api_error(StatusCode::NOT_FOUND, "unknown session", None).into_response();
     }
     drop(sessions_read);
-    choose_username_page(&q.session, q.error.as_deref()).into_response()
+    let next = theme_next_from_uri(&uri);
+    choose_username_page(&q.session, q.error.as_deref(), theme_from_jar(&jar), &next).into_response()
 }
 
 #[derive(Debug, Deserialize)]
@@ -396,6 +413,7 @@ pub struct ChooseUsernameForm {
 
 pub async fn post_choose_username(
     State(state): State<AppState>,
+    jar: CookieJar,
     Form(form): Form<ChooseUsernameForm>,
 ) -> impl IntoResponse {
     let canon_user = match parse_username(&form.username) {
@@ -477,7 +495,7 @@ pub async fn post_choose_username(
         s.complete = Some((canon_user.clone(), bearer.clone()));
     }
 
-    js_signed_in_fragment(&bearer).into_response()
+    js_signed_in_fragment(&bearer, &jar).into_response()
 }
 
 /// Start a browser-only OAuth flow (no CLI polling). Sets session cookie on success.
@@ -569,8 +587,9 @@ pub async fn get_pending_session(
     .into_response()
 }
 
-pub async fn get_auth_complete() -> impl IntoResponse {
-    auth_complete_page()
+pub async fn get_auth_complete(jar: CookieJar, uri: Uri) -> impl IntoResponse {
+    let next = theme_next_from_uri(&uri);
+    auth_complete_page(theme_from_jar(&jar), &next).into_response()
 }
 
 pub async fn get_whoami(State(state): State<AppState>, headers: HeaderMap) -> impl IntoResponse {
diff --git a/server/src/api/helpers.rs b/server/src/api/helpers.rs
index 81e2a55fa3abb8609b4099f91a989480336e11eb..9b71491e9f9efc44a2a4beba09be8f64bd2ff2ee 100644
--- a/server/src/api/helpers.rs
+++ b/server/src/api/helpers.rs
@@ -39,6 +39,55 @@ pub fn item_path_for_api(item: &str) -> String {
     }
 }
 
+/// Same as [`item_path_for_api`], but for private rooms ontology items are prefixed with
+/// `/r/{short}/{slug}` so the URL matches the web app (`/r/…/~/…` routes).
+pub fn item_path_for_api_in_room(item: &str, room_wire: &str) -> String {
+    let room = room_wire.trim();
+    if room.is_empty() || room == "public" {
+        return item_path_for_api(item);
+    }
+    let Some((short, slug)) = room.split_once('/') else {
+        return item_path_for_api(item);
+    };
+    if short.is_empty() || slug.is_empty() {
+        return item_path_for_api(item);
+    }
+    let Some(c) = CanonicalItemUrl::parse(item) else {
+        return item_path_for_api(item);
+    };
+    let root = CanonicalItemUrl::ontology_root();
+    let item_norm = c.as_str().trim_end_matches('/');
+    let root_norm = root.as_str().trim_end_matches('/');
+    if let Some(tail) = c.tilde_tail() {
+        return if tail.is_empty() {
+            format!("https://slug.social/r/{short}/{slug}/~")
+        } else {
+            format!("https://slug.social/r/{short}/{slug}/~/{}", tail)
+        };
+    }
+    if item_norm == root_norm {
+        return format!("https://slug.social/r/{short}/{slug}/~");
+    }
+    item_path_for_api(item)
+}
+
+/// Absolute thread URL for forum JSON (`/t/…` vs `/r/…/t/…`).
+pub fn forum_thread_web_url(room_wire: &str, thread_tag: &str) -> String {
+    let room = room_wire.trim();
+    let tag = thread_tag.trim().trim_start_matches('#');
+    if room.is_empty() || room == "public" {
+        format!("https://slug.social/t/{tag}")
+    } else if let Some((short, slug)) = room.split_once('/') {
+        if short.is_empty() || slug.is_empty() {
+            format!("https://slug.social/t/{tag}")
+        } else {
+            format!("https://slug.social/r/{short}/{slug}/t/{tag}")
+        }
+    } else {
+        format!("https://slug.social/t/{tag}")
+    }
+}
+
 /// Resolve an item path as a first-class canonical path.
 pub fn resolve_item(item: &str) -> Result<String, String> {
     let canonical = canonicalize_item(item);
@@ -188,3 +237,52 @@ pub fn vote_touches_path(a: &str, b: &str, parent_canon: &str) -> bool {
     let under = |item: &str| item == parent_canon || item.starts_with(&format!("{}/", parent_canon));
     under(a) || under(b)
 }
+
+#[cfg(test)]
+mod wire_url_tests {
+    use super::{forum_thread_web_url, item_path_for_api_in_room};
+
+    #[test]
+    fn public_room_unchanged() {
+        let u = "https://slug.social/~/a/b";
+        assert_eq!(item_path_for_api_in_room(u, "public"), u);
+    }
+
+    #[test]
+    fn private_room_prefixes_ontology() {
+        assert_eq!(
+            item_path_for_api_in_room("https://slug.social/~/topic/x", "9ab12cd/my-room"),
+            "https://slug.social/r/9ab12cd/my-room/~/topic/x"
+        );
+    }
+
+    #[test]
+    fn private_room_ontology_root() {
+        assert_eq!(
+            item_path_for_api_in_room("https://slug.social/~", "9ab12cd/my-room"),
+            "https://slug.social/r/9ab12cd/my-room/~"
+        );
+        assert_eq!(
+            item_path_for_api_in_room("https://slug.social/~/", "9ab12cd/my-room"),
+            "https://slug.social/r/9ab12cd/my-room/~"
+        );
+    }
+
+    #[test]
+    fn external_url_untouched_in_private_room() {
+        let u = "https://example.com/z";
+        assert_eq!(item_path_for_api_in_room(u, "9ab12cd/my-room"), u);
+    }
+
+    #[test]
+    fn forum_web_public_vs_room() {
+        assert_eq!(
+            forum_thread_web_url("public", "debate"),
+            "https://slug.social/t/debate"
+        );
+        assert_eq!(
+            forum_thread_web_url("9ab12cd/my-room", "#debate"),
+            "https://slug.social/r/9ab12cd/my-room/t/debate"
+        );
+    }
+}
diff --git a/server/src/api/rpc.rs b/server/src/api/rpc.rs
index 31f5fcfb4eaf4df0a9cbac532dd3dedfe3611810..5b91f5836625eedbb1cd9423168046e3fb576c17 100644
--- a/server/src/api/rpc.rs
+++ b/server/src/api/rpc.rs
@@ -27,8 +27,9 @@ use crate::{
 
 use super::auth::verify_bearer_principal;
 use super::helpers::{
-    compute_connectivity_stats, is_pair_voted, item_path_for_api, now_ms, paginate_rankings,
-    parse_parent_specs, pick_random_distinct, resolve_item, vote_touches_path,
+    compute_connectivity_stats, forum_thread_web_url, is_pair_voted, item_path_for_api,
+    item_path_for_api_in_room, now_ms, paginate_rankings, parse_parent_specs, pick_random_distinct,
+    resolve_item, vote_touches_path,
 };
 use super::validate::{normalize_room_and_thread, validate_ingest_document};
 
@@ -148,6 +149,7 @@ fn compute_scope_rank_changes(
     parent: &str,
     before: &crate::scope_rank::ChildrenRankings,
     after: &crate::scope_rank::ChildrenRankings,
+    room_wire: &str,
 ) -> Option<ScopeRankChanges> {
     fn build_positions(rankings: &crate::scope_rank::ChildrenRankings) -> HashMap<String, Option<RankPosition>> {
         let mut map = HashMap::new();
@@ -182,7 +184,7 @@ fn compute_scope_rank_changes(
         };
         if changed {
             changes.push(RankChange {
-                item: item_path_for_api(&item),
+                item: item_path_for_api_in_room(&item, room_wire),
                 before: b,
                 after: a,
             });
@@ -204,7 +206,7 @@ fn compute_scope_rank_changes(
         parent: if parent.is_empty() {
             "/".to_string()
         } else {
-            item_path_for_api(parent)
+            item_path_for_api_in_room(parent, room_wire)
         },
         changes,
     })
@@ -256,6 +258,7 @@ fn build_rank_response_for_content(
     offset: usize,
     limit: Option<usize>,
     want_percent: bool,
+    room_wire: &str,
 ) -> Result<RankResponse, RpcErr> {
     let parent_owned = parent.map(|s| s.to_string());
     let specs = parse_parent_specs(parent_owned.as_ref());
@@ -299,7 +302,7 @@ fn build_rank_response_for_content(
                     .ranked
                     .into_iter()
                     .map(|r| RankRow {
-                        item: item_path_for_api(r.item.as_str()),
+                        item: item_path_for_api_in_room(r.item.as_str(), room_wire),
                         percent: if want_percent {
                             Some((r.score / max_score) * 100.0)
                         } else {
@@ -315,7 +318,7 @@ fn build_rank_response_for_content(
     let prefixed_unranked: Vec<String> = rankings
         .unranked_items
         .into_iter()
-        .map(|s| item_path_for_api(s.as_str()))
+        .map(|s| item_path_for_api_in_room(s.as_str(), room_wire))
         .collect();
 
     let (components, unranked_items) = if offset > 0 || limit.is_some() {
@@ -522,7 +525,7 @@ async fn rpc_post(
             .filter_map(|p| {
                 let before = pre_rankings.get(p)?;
                 let after = crate::scope_rank::build_children_rankings(content, p);
-                compute_scope_rank_changes(p.as_str(), before, &after)
+                compute_scope_rank_changes(p.as_str(), before, &after, &room_key)
             })
             .collect();
         if v.is_empty() { None } else { Some(v) }
@@ -530,14 +533,28 @@ async fn rpc_post(
         None
     };
 
+    let (pair_hint, rank_hint, web_url) = if room_key == "public" {
+        (
+            "npx slugsocial public garden pair".to_string(),
+            "npx slugsocial public garden rank".to_string(),
+            forum_thread_web_url("public", &thread_id),
+        )
+    } else {
+        (
+            format!("npx slugsocial private {room_key} garden pair"),
+            format!("npx slugsocial private {room_key} garden rank"),
+            forum_thread_web_url(&room_key, &thread_id),
+        )
+    };
+
     Ok(RpcResult::PostOk {
         events_appended,
         ranking_changes,
         threads: vec![format!("#{}", thread_id)],
         next: NextMoves {
-            pair: "npx slugsocial public garden pair".to_string(),
-            rank: "npx slugsocial public garden rank".to_string(),
-            web: format!("https://slug.social/t/{}", thread_id),
+            pair: pair_hint,
+            rank: rank_hint,
+            web: web_url,
         },
     })
 }
@@ -609,7 +626,7 @@ async fn rpc_check(
         raw: v.raw_text.clone(),
         principal,
         delegate,
-        room_id: room_key,
+        room_id: room_key.clone(),
         thread_tag: thread_id.clone(),
     });
 
@@ -647,7 +664,7 @@ async fn rpc_check(
                         .ranked
                         .into_iter()
                         .map(|r| RankRow {
-                            item: item_path_for_api(r.item.as_str()),
+                            item: item_path_for_api_in_room(r.item.as_str(), &room_key),
                             score: r.score,
                             percent: None,
                         })
@@ -655,25 +672,35 @@ async fn rpc_check(
                 })
                 .collect();
             CheckScopeRanking {
-                parent: item_path_for_api(parent.as_str()),
+                parent: item_path_for_api_in_room(parent.as_str(), &room_key),
                 components,
                 unranked_items: scoped
                     .unranked_items
                     .into_iter()
-                    .map(|it| item_path_for_api(it.as_str()))
+                    .map(|it| item_path_for_api_in_room(it.as_str(), &room_key))
                     .collect(),
             }
         })
         .collect();
 
+    let check_next = if room_key == "public" {
+        vec![
+            "npx slugsocial public forum post <TAG> --delegate <uuid:rig:model>".to_string(),
+            "npx slugsocial public forum list".to_string(),
+            forum_thread_web_url("public", &thread_id),
+        ]
+    } else {
+        vec![
+            format!("npx slugsocial private {room_key} forum post <TAG> --delegate <uuid:rig:model>"),
+            format!("npx slugsocial private {room_key} forum list"),
+            forum_thread_web_url(&room_key, &thread_id),
+        ]
+    };
+
     Ok(RpcResult::CheckOk {
         rankings,
         threads: vec![format!("#{}", thread_id)],
-        next: vec![
-            "npx slugsocial public forum post <TAG> --delegate <uuid:rig:model>".to_string(),
-            "npx slugsocial public forum list".to_string(),
-            format!("https://slug.social/t/{}", thread_id),
-        ],
+        next: check_next,
     })
 }
 
@@ -690,7 +717,7 @@ fn rpc_list_forum_threads(reduced: &ReducerState, room: &str) -> ThreadsResponse
         .map(|((_, tag), ts)| ThreadSummary {
             thread: format!("#{tag}"),
             last_activity_ts: ts.last_activity_ts,
-            web: format!("https://slug.social/t/{}", tag),
+            web: forum_thread_web_url(room, tag),
         })
         .collect();
     out.sort_by(|a, b| b.last_activity_ts.cmp(&a.last_activity_ts));
@@ -1031,8 +1058,8 @@ async fn rpc_get_pair(state: &AppState, room: String, parent_path: String) -> Re
         .collect();
     let cs = compute_connectivity_stats(&content.ranking_group, &pool);
     Ok(RpcResult::Pair(PairResponse {
-        left: item_path_for_api(&left),
-        right: item_path_for_api(&right),
+        left: item_path_for_api_in_room(&left, &room),
+        right: item_path_for_api_in_room(&right, &room),
         left_body: lb,
         right_body: rb,
         threads: th,
@@ -1088,6 +1115,7 @@ pub async fn handle_rpc_batch(
                     offset.unwrap_or(0),
                     limit,
                     percent.unwrap_or(false),
+                    &room,
                 ) {
                     Ok(r) => line_ok(RpcResult::GardenRank(r)),
                     Err((e, h)) => line_err(e, h),
@@ -1109,7 +1137,7 @@ pub async fn handle_rpc_batch(
                 if !content.items.contains(&item) {
                     line_err(
                         "item not found",
-                        Some(format!("{} does not exist", item_path_for_api(&item_str))),
+                        Some(format!("{} does not exist", item_path_for_api_in_room(&item_str, &room))),
                     )
                 } else {
                     const MAX_ITEM_BODY: usize = 10_000;
@@ -1132,7 +1160,7 @@ pub async fn handle_rpc_batch(
                         .map(|s| s.iter().cloned().collect())
                         .unwrap_or_default();
                     line_ok(RpcResult::GardenItem(ItemResponse {
-                        item: item_str,
+                        item: item_path_for_api_in_room(&item_str, &room),
                         body,
                         truncated,
                         body_len,
@@ -1525,7 +1553,11 @@ pub async fn handle_rpc_batch(
                     let range = (top - bot).max(1e-12);
                     for r in items {
                         let pct = want_percent.then(|| ((r.score - bot) / range * 100.0).clamp(0.0, 100.0));
-                        ranked.push(RankRow { item: item_path_for_api(r.item.as_str()), score: r.score, percent: pct });
+                        ranked.push(RankRow {
+                            item: item_path_for_api_in_room(r.item.as_str(), &room),
+                            score: r.score,
+                            percent: pct,
+                        });
                     }
                 }
 
@@ -1542,7 +1574,7 @@ pub async fn handle_rpc_batch(
                 let page: Vec<RankRow> = ranked
                     .into_iter()
                     .chain(unranked.into_iter().map(|it| RankRow {
-                        item: item_path_for_api(&it),
+                        item: item_path_for_api_in_room(&it, &room),
                         score: 0.0,
                         percent: want_percent.then_some(0.0),
                     }))
@@ -1586,7 +1618,7 @@ pub async fn handle_rpc_batch(
                 if !content.items.contains(&item) {
                     line_err(
                         "item not found",
-                        Some(format!("{} does not exist", item_path_for_api(&item_str))),
+                        Some(format!("{} does not exist", item_path_for_api_in_room(&item_str, &room))),
                     )
                 } else {
                     let votes: Vec<VoteRow> = content
@@ -1597,8 +1629,8 @@ pub async fn handle_rpc_batch(
                                 .take(limit)
                                 .map(|v| VoteRow {
                                     ts: v.ts,
-                                    a: v.a.as_str().to_string(),
-                                    b: v.b.as_str().to_string(),
+                                    a: item_path_for_api_in_room(v.a.as_str(), &room),
+                                    b: item_path_for_api_in_room(v.b.as_str(), &room),
                                     ratio: format!("{}:{}", v.ratio_left, v.ratio_right),
                                     actor: Some(v.principal.clone()),
                                     body: v.body.clone(),
@@ -1608,7 +1640,7 @@ pub async fn handle_rpc_batch(
                         })
                         .unwrap_or_default();
                     line_ok(RpcResult::Matchup(MatchupResponse {
-                        item: item_path_for_api(&item_str),
+                        item: item_path_for_api_in_room(&item_str, &room),
                         votes,
                     }))
                 }
@@ -1635,8 +1667,8 @@ pub async fn handle_rpc_batch(
                                     if a == item_str || b == item_str {
                                         Some(VoteRow {
                                             ts: e.ts,
-                                            a: item_path_for_api(&a),
-                                            b: item_path_for_api(&b),
+                                            a: item_path_for_api_in_room(&a, &room),
+                                            b: item_path_for_api_in_room(&b, &room),
                                             ratio: format!("{}:{}", ratio_left, ratio_right),
                                             actor: reduced.ingests_by_id.get(&e.post_id).map(|ing| ing.principal.clone()),
                                             body: explanation,
@@ -1672,7 +1704,7 @@ pub async fn handle_rpc_batch(
                     }
                 }).collect();
                 line_ok(RpcResult::RankHistory(RankHistoryResponse {
-                    item: item_path_for_api(&item_str),
+                    item: item_path_for_api_in_room(&item_str, &room),
                     history,
                 }))
                 }
@@ -1691,6 +1723,10 @@ pub async fn handle_rpc_batch(
                     .map(|p| p.as_str().to_string())
                     .collect();
                 paths.sort();
+                let paths: Vec<String> = paths
+                    .into_iter()
+                    .map(|p| item_path_for_api_in_room(&p, &room))
+                    .collect();
                 line_ok(RpcResult::Leaves(LeavesResponse { paths }))
                 }
             },
@@ -1707,10 +1743,21 @@ pub async fn handle_rpc_batch(
                         let mut v: Vec<PathSummary> = roots.iter()
                             .map(|path| {
                                 let children = content.item_children.get(path.as_str()).map(|s| s.len()).unwrap_or(0);
+                                let path_label = CanonicalItemUrl::parse(path.as_str())
+                                    .and_then(|c| {
+                                        c.tilde_tail().map(|t| {
+                                            if t.is_empty() {
+                                                "~/".to_string()
+                                            } else {
+                                                format!("~/{}", t)
+                                            }
+                                        })
+                                    })
+                                    .unwrap_or_else(|| path.to_string());
                                 PathSummary {
-                                    path: format!("~/{}", path),
+                                    path: path_label,
                                     children,
-                                    web: format!("https://slug.social/~/{}", path),
+                                    web: item_path_for_api_in_room(path.as_str(), &room),
                                 }
                             }).collect();
                         v.sort_by(|a, b| a.path.cmp(&b.path));
@@ -1743,8 +1790,8 @@ pub async fn handle_rpc_batch(
                     .take(limit)
                     .map(|v| VoteRow {
                         ts: v.ts,
-                        a: v.a.as_str().to_string(),
-                        b: v.b.as_str().to_string(),
+                        a: item_path_for_api_in_room(v.a.as_str(), &room),
+                        b: item_path_for_api_in_room(v.b.as_str(), &room),
                         ratio: format!("{}:{}", v.ratio_left, v.ratio_right),
                         actor: Some(v.principal.clone()),
                         body: v.body.clone(),
diff --git a/server/src/html/auth.rs b/server/src/html/auth.rs
index d57b1c725ce3e06b1d904882b9388c3da48d85cb..5df77c76b89ed2bb11d936e1dbb804d50a0e79a1 100644
--- a/server/src/html/auth.rs
+++ b/server/src/html/auth.rs
@@ -23,7 +23,7 @@ fn form_inner(session: &str, error: Option<&str>) -> Markup {
     }
 }
 
-pub fn choose_username_page(session: &str, error: Option<&str>) -> Markup {
+pub fn choose_username_page(session: &str, error: Option<&str>, theme: &str, theme_next: &str) -> Markup {
     let body = html! {
         nav.breadcrumb {
             a href="/" { "slug.social" }
@@ -36,7 +36,7 @@ pub fn choose_username_page(session: &str, error: Option<&str>) -> Markup {
             (form_inner(session, error))
         }
     };
-    super::layout("join — slug.social", "view-auth", body, None)
+    super::layout("join — slug.social", "view-auth", body, None, theme, theme_next)
 }
 
 /// Fragment returned to the poem JS on error — replaces the form's innerHTML.
@@ -52,7 +52,7 @@ pub fn auth_signed_in_fragment() -> Markup {
     }
 }
 
-pub fn auth_complete_page() -> Markup {
+pub fn auth_complete_page(theme: &str, theme_next: &str) -> Markup {
     let body = html! {
         nav.breadcrumb {
             a href="/" { "slug.social" }
@@ -63,5 +63,5 @@ pub fn auth_complete_page() -> Markup {
         p { "Return to your terminal — your agent is polling and will collect your token automatically." }
         p.auth-hint { "You can close this tab." }
     };
-    super::layout("signed in — slug.social", "view-auth", body, None)
+    super::layout("signed in — slug.social", "view-auth", body, None, theme, theme_next)
 }
diff --git a/server/src/html/editor.rs b/server/src/html/editor.rs
index 07f6ab3b778f07f60765fa3f39060ebc5f72bc1a..ecdd226b1b17d5f11d1b79f99add5759ef918281 100644
--- a/server/src/html/editor.rs
+++ b/server/src/html/editor.rs
@@ -1,8 +1,10 @@
 use axum::{
     extract::State,
+    http::Uri,
     response::{Html, IntoResponse},
     Form,
 };
+use axum_extra::extract::cookie::CookieJar;
 use maud::{html, Markup};
 use serde::Deserialize;
 
@@ -13,7 +15,7 @@ use crate::{
     state::AppState,
 };
 
-use super::{bc_segment, layout};
+use super::{bc_segment, layout, theme_from_jar, theme_next_from_uri};
 
 fn bc_try() -> Markup {
     html! {
@@ -23,7 +25,7 @@ fn bc_try() -> Markup {
 }
 
 /// The interactive editor page — `/try`.
-pub async fn editor_page() -> impl IntoResponse {
+pub async fn editor_page(jar: CookieJar, uri: Uri) -> impl IntoResponse {
     let page = layout(
         "try — slug.social",
         "view-thread",
@@ -68,6 +70,8 @@ pub async fn editor_page() -> impl IntoResponse {
 "#)) }
         },
         None,
+        theme_from_jar(&jar),
+        &theme_next_from_uri(&uri),
     );
     Html(page.into_string())
 }
diff --git a/server/src/html/forum.rs b/server/src/html/forum.rs
index 5c5f9e2ba0e5cb1d661c113117988ec80c01deca..368b1016eb43d83e9ff39464ff6164fa9a8b558a 100644
--- a/server/src/html/forum.rs
+++ b/server/src/html/forum.rs
@@ -1,6 +1,6 @@
 use axum::{
     extract::{Path, Query, State},
-    http::{HeaderMap, StatusCode},
+    http::{HeaderMap, StatusCode, Uri},
     response::{Html, IntoResponse},
 };
 use axum_extra::extract::cookie::CookieJar;
@@ -19,7 +19,7 @@ use crate::{
 
 use super::{
     bc_segment, bc_threads, cli_panel, layout, now_ms, profile_href, recency_class,
-    render_linkified_with_embeds_in_scope, JsBuilder,
+    render_linkified_with_embeds_in_scope, theme_from_jar, theme_next_from_uri, JsBuilder,
 };
 
 #[derive(Clone)]
@@ -577,6 +577,7 @@ pub async fn home(
     State(state): State<AppState>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let now = now_ms();
     let reduced = state.reduced.read().await;
@@ -624,6 +625,8 @@ pub async fn home(
             (cli_panel("npx slugsocial public forum list"))
         },
         None,
+        theme_from_jar(&jar),
+        &theme_next_from_uri(&uri),
     );
     Html(page.into_string())
 }
@@ -679,6 +682,7 @@ async fn thread_view_inner(
     nav: ThreadNav,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let tag = canonicalize_tag(&tag);
     let scope = nav.scope();
@@ -778,6 +782,8 @@ async fn thread_view_inner(
             (cli_panel(&cli))
         },
         None,
+        theme_from_jar(&jar),
+        &theme_next_from_uri(&uri),
     );
     Html(page.into_string()).into_response()
 }
@@ -789,8 +795,9 @@ pub async fn thread_view(
     Query(q): Query<ThreadViewQuery>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
-    thread_view_inner(state, tag, q, ThreadNav::public(), headers, jar).await
+    thread_view_inner(state, tag, q, ThreadNav::public(), headers, jar, uri).await
 }
 
 /// Room thread — `/r/:short/:slug/t/:tag`
@@ -800,31 +807,39 @@ pub async fn room_thread_view(
     Query(q): Query<ThreadViewQuery>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let room_id = format!("{room_short}/{room_slug}");
     let reduced = state.reduced.read().await;
     let user = optional_principal(&headers, &jar, &reduced);
     if !user_can_view_room(&reduced, &room_id, user.as_deref()) {
         drop(reduced);
-        return room_not_found_page().into_response();
+        return room_not_found_page(&jar, &uri).into_response();
     }
     drop(reduced);
     let Some(nav) = ThreadNav::from_room_id(&room_id) else {
         return (StatusCode::NOT_FOUND, "bad room path").into_response();
     };
-    thread_view_inner(state, tag, q, nav, headers, jar)
+    thread_view_inner(state, tag, q, nav, headers, jar, uri)
         .await
         .into_response()
 }
 
-fn room_not_found_page() -> impl IntoResponse {
+fn room_not_found_page(jar: &CookieJar, uri: &Uri) -> impl IntoResponse {
     let body = html! {
         nav class="breadcrumb" { a href="/" { "slug.social" } }
         h1 { "not found" }
         p { "The requested page could not be found." }
         p { a href="/" { "home" } }
     };
-    let page = layout("not found — slug.social", "view-thread", body, None);
+    let page = layout(
+        "not found — slug.social",
+        "view-thread",
+        body,
+        None,
+        theme_from_jar(jar),
+        &theme_next_from_uri(uri),
+    );
     (StatusCode::NOT_FOUND, Html(page.into_string()))
 }
 
@@ -834,6 +849,7 @@ pub async fn room_page(
     Path((room_short, room_slug)): Path<(String, String)>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let room_id = format!("{room_short}/{room_slug}");
     let now = now_ms();
@@ -845,7 +861,7 @@ pub async fn room_page(
     let user = optional_principal(&headers, &jar, &reduced);
     if !user_can_view_room(&reduced, &room_id, user.as_deref()) {
         drop(reduced);
-        return room_not_found_page().into_response();
+        return room_not_found_page(&jar, &uri).into_response();
     }
     let scope = ScopeId::Room(room_id.clone());
     let mut rows = collect_thread_rows_for_scope(&reduced, &scope, now);
@@ -902,6 +918,8 @@ pub async fn room_page(
             (cli_panel(&audit_cli))
         },
         None,
+        theme_from_jar(&jar),
+        &theme_next_from_uri(&uri),
     );
     Html(page.into_string()).into_response()
 }
@@ -943,6 +961,8 @@ async fn thread_post_view_inner(
     index_str: String,
     nav: ThreadNav,
     viewer: Option<String>,
+    jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let tag = canonicalize_tag(&tag);
     let index: usize = index_str.parse().unwrap_or(0);
@@ -987,6 +1007,8 @@ async fn thread_post_view_inner(
             }
         },
         None,
+        theme_from_jar(&jar),
+        &theme_next_from_uri(&uri),
     );
     Html(page.into_string()).into_response()
 }
@@ -996,11 +1018,12 @@ pub async fn thread_post_view(
     Path((tag, index_str)): Path<(String, String)>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let reduced = state.reduced.read().await;
     let viewer = optional_principal(&headers, &jar, &reduced);
     drop(reduced);
-    thread_post_view_inner(state, tag, index_str, ThreadNav::public(), viewer)
+    thread_post_view_inner(state, tag, index_str, ThreadNav::public(), viewer, jar, uri)
         .await
 }
 
@@ -1009,19 +1032,20 @@ pub async fn room_thread_post_view(
     Path((room_short, room_slug, tag, index_str)): Path<(String, String, String, String)>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let room_id = format!("{room_short}/{room_slug}");
     let reduced = state.reduced.read().await;
     let user = optional_principal(&headers, &jar, &reduced);
     if !user_can_view_room(&reduced, &room_id, user.as_deref()) {
         drop(reduced);
-        return room_not_found_page().into_response();
+        return room_not_found_page(&jar, &uri).into_response();
     }
     drop(reduced);
     let Some(nav) = ThreadNav::from_room_id(&room_id) else {
         return (StatusCode::NOT_FOUND, "bad room path").into_response();
     };
-    thread_post_view_inner(state, tag, index_str, nav, user)
+    thread_post_view_inner(state, tag, index_str, nav, user, jar, uri)
         .await
         .into_response()
 }
@@ -1193,6 +1217,7 @@ pub async fn user_profile_page(
     Path(username): Path<String>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let canon = match parse_username(&username) {
         Ok(u) => u,
@@ -1270,6 +1295,8 @@ pub async fn user_profile_page(
             (cli_panel(&format!("npx slugsocial public forum list")))
         },
         None,
+        theme_from_jar(&jar),
+        &theme_next_from_uri(&uri),
     );
     Html(page.into_string()).into_response()
 }
@@ -1292,13 +1319,14 @@ pub async fn room_thread_post_expand(
     Path((room_short, room_slug, tag, index_str)): Path<(String, String, String, String)>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let room_id = format!("{room_short}/{room_slug}");
     let reduced = state.reduced.read().await;
     let user = optional_principal(&headers, &jar, &reduced);
     if !user_can_view_room(&reduced, &room_id, user.as_deref()) {
         drop(reduced);
-        return room_not_found_page().into_response();
+        return room_not_found_page(&jar, &uri).into_response();
     }
     let Some(nav) = ThreadNav::from_room_id(&room_id) else {
         drop(reduced);
@@ -1328,13 +1356,14 @@ pub async fn room_thread_post_expand_deleted(
     Path((room_short, room_slug, tag, index_str)): Path<(String, String, String, String)>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let room_id = format!("{room_short}/{room_slug}");
     let reduced = state.reduced.read().await;
     let user = optional_principal(&headers, &jar, &reduced);
     if !user_can_view_room(&reduced, &room_id, user.as_deref()) {
         drop(reduced);
-        return room_not_found_page().into_response();
+        return room_not_found_page(&jar, &uri).into_response();
     }
     let Some(nav) = ThreadNav::from_room_id(&room_id) else {
         drop(reduced);
@@ -1364,13 +1393,14 @@ pub async fn room_thread_post_collapse_deleted(
     Path((room_short, room_slug, tag, index_str)): Path<(String, String, String, String)>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let room_id = format!("{room_short}/{room_slug}");
     let reduced = state.reduced.read().await;
     let user = optional_principal(&headers, &jar, &reduced);
     if !user_can_view_room(&reduced, &room_id, user.as_deref()) {
         drop(reduced);
-        return room_not_found_page().into_response();
+        return room_not_found_page(&jar, &uri).into_response();
     }
     let Some(nav) = ThreadNav::from_room_id(&room_id) else {
         drop(reduced);
diff --git a/server/src/html/garden.rs b/server/src/html/garden.rs
index e08f068ae04f5a2542ec2c43c240f931f87146bf..9b4789a79c3e293cbfc5f033a0eac8650320d94d 100644
--- a/server/src/html/garden.rs
+++ b/server/src/html/garden.rs
@@ -1,6 +1,6 @@
 use axum::{
     extract::{Path, State},
-    http::{HeaderMap, StatusCode},
+    http::{HeaderMap, StatusCode, Uri},
     response::{Html, IntoResponse},
 };
 use axum_extra::extract::cookie::CookieJar;
@@ -20,7 +20,8 @@ use crate::{
 
 use super::{
     bc_path, bc_segment, cli_panel, layout, now_ms, ratio_pct,
-    render_linkified_with_embeds_in_scope, breadcrumb_path::OntologyPath,
+    render_linkified_with_embeds_in_scope, theme_from_jar, theme_next_from_uri,
+    breadcrumb_path::OntologyPath,
     forum::ThreadNav,
 };
 
@@ -59,14 +60,21 @@ fn scoped_bc_path(path: &OntologyPath, nav: &ThreadNav) -> maud::Markup {
     }
 }
 
-fn room_not_found_page() -> impl IntoResponse {
+fn room_not_found_page(jar: &CookieJar, uri: &Uri) -> impl IntoResponse {
     let body = html! {
         nav class="breadcrumb" { a href="/" { "slug.social" } }
         h1 { "not found" }
         p { "The requested page could not be found." }
         p { a href="/" { "home" } }
     };
-    let page = layout("not found — slug.social", "view-thread", body, None);
+    let page = layout(
+        "not found — slug.social",
+        "view-thread",
+        body,
+        None,
+        theme_from_jar(jar),
+        &theme_next_from_uri(uri),
+    );
     (StatusCode::NOT_FOUND, Html(page.into_string()))
 }
 
@@ -81,7 +89,11 @@ fn user_can_view_room(reduced: &ReducerState, room_id: &str, username: Option<&s
 }
 
 /// Ontology index — root-level paths. Private (UUID) roots are excluded.
-pub async fn garden_index(State(state): State<AppState>) -> impl IntoResponse {
+pub async fn garden_index(
+    State(state): State<AppState>,
+    jar: CookieJar,
+    uri: Uri,
+) -> impl IntoResponse {
     let nav = ThreadNav::public();
     let child_rankings = {
         let reduced = state.reduced.read().await;
@@ -130,6 +142,8 @@ pub async fn garden_index(State(state): State<AppState>) -> impl IntoResponse {
             (cli_panel("npx slugsocial garden tree"))
         },
         None,
+        theme_from_jar(&jar),
+        &theme_next_from_uri(&uri),
     );
     Html(page.into_string())
 }
@@ -138,9 +152,11 @@ pub async fn garden_index(State(state): State<AppState>) -> impl IntoResponse {
 pub async fn ontology_path(
     State(state): State<AppState>,
     Path(path): Path<String>,
+    jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let path = OntologyPath::from_input(&path);
-    render_scope_view(state, path, ThreadNav::public()).await
+    render_scope_view(state, path, ThreadNav::public(), jar, uri).await
 }
 
 pub async fn room_garden_index(
@@ -148,19 +164,20 @@ pub async fn room_garden_index(
     Path((room_short, room_slug)): Path<(String, String)>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let room_id = format!("{room_short}/{room_slug}");
     let reduced = state.reduced.read().await;
     let user = optional_principal(&headers, &jar, &reduced);
     if !user_can_view_room(&reduced, &room_id, user.as_deref()) {
         drop(reduced);
-        return room_not_found_page().into_response();
+        return room_not_found_page(&jar, &uri).into_response();
     }
     drop(reduced);
     let Some(nav) = ThreadNav::from_room_id(&room_id) else {
         return (StatusCode::NOT_FOUND, "bad room path").into_response();
     };
-    render_scope_view(state, OntologyPath::root(), nav).await
+    render_scope_view(state, OntologyPath::root(), nav, jar, uri).await
 }
 
 pub async fn room_ontology_path(
@@ -168,20 +185,21 @@ pub async fn room_ontology_path(
     Path((room_short, room_slug, path)): Path<(String, String, String)>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let room_id = format!("{room_short}/{room_slug}");
     let reduced = state.reduced.read().await;
     let user = optional_principal(&headers, &jar, &reduced);
     if !user_can_view_room(&reduced, &room_id, user.as_deref()) {
         drop(reduced);
-        return room_not_found_page().into_response();
+        return room_not_found_page(&jar, &uri).into_response();
     }
     drop(reduced);
     let Some(nav) = ThreadNav::from_room_id(&room_id) else {
         return (StatusCode::NOT_FOUND, "bad room path").into_response();
     };
     let path = OntologyPath::from_input(&path);
-    render_scope_view(state, path, nav).await
+    render_scope_view(state, path, nav, jar, uri).await
 }
 
 #[derive(Debug, Clone)]
@@ -375,6 +393,8 @@ async fn render_scope_view(
     state: AppState,
     path: OntologyPath,
     nav: ThreadNav,
+    jar: CookieJar,
+    uri: Uri,
 ) -> axum::response::Response {
     let scope = nav.scope();
     let model = {
@@ -525,6 +545,8 @@ async fn render_scope_view(
             (cli_panel(&cli))
         },
         None,
+        theme_from_jar(&jar),
+        &theme_next_from_uri(&uri),
     );
 
     Html(page.into_string()).into_response()
diff --git a/server/src/html/mod.rs b/server/src/html/mod.rs
index a8fd73433d120b07351dd027faf0b25f8f101321..53041a0cf0b30e6f20749c92ecc15a4e9ac56e09 100644
--- a/server/src/html/mod.rs
+++ b/server/src/html/mod.rs
@@ -1,10 +1,13 @@
 use axum::{
     body::Body,
     extract::Path,
-    http::{header, StatusCode},
+    http::{header, HeaderValue, StatusCode, Uri},
     response::{IntoResponse, Response},
+    Form,
 };
+use axum_extra::extract::cookie::CookieJar;
 use maud::{html, Markup, DOCTYPE};
+use serde::Deserialize;
 use std::collections::HashSet;
 
 mod auth;
@@ -33,6 +36,75 @@ pub(crate) fn profile_href(username: &str) -> String {
     format!("/u/{username}")
 }
 
+/// Cookie name for UI theme (must match document.cookie migration in [`layout`]).
+pub const SLUG_THEME_COOKIE: &str = "slug-theme";
+
+/// Normalize a requested theme id to a known stylesheet key.
+pub fn normalize_theme(raw: &str) -> &'static str {
+    match raw {
+        "retro" => "retro",
+        "retro_craft" => "retro_craft",
+        _ => "default",
+    }
+}
+
+/// Resolved theme for rendering and cookie re-issue.
+pub fn theme_from_jar(jar: &CookieJar) -> &'static str {
+    jar.get(SLUG_THEME_COOKIE)
+        .map(|c| normalize_theme(c.value()))
+        .unwrap_or("default")
+}
+
+/// `Path` + optional `?query` for round-tripping after `POST /theme`.
+pub fn theme_next_from_uri(uri: &Uri) -> String {
+    uri.path_and_query()
+        .map(|pq| pq.as_str().to_string())
+        .filter(|s| !s.is_empty())
+        .unwrap_or_else(|| "/".to_string())
+}
+
+/// `Set-Cookie` for a validated theme (ASCII cookie value).
+pub fn theme_cookie_header_value(theme: &str) -> HeaderValue {
+    let t = normalize_theme(theme);
+    let s = format!("{SLUG_THEME_COOKIE}={t}; Path=/; SameSite=Lax; Max-Age=31536000");
+    HeaderValue::from_str(&s).expect("theme cookie must be ASCII")
+}
+
+/// Re-issue theme cookie on responses that also set `slug_session`, so login does not drop theme.
+pub fn theme_cookie_header_from_jar(jar: &CookieJar) -> Option<HeaderValue> {
+    let c = jar.get(SLUG_THEME_COOKIE)?;
+    Some(theme_cookie_header_value(c.value()))
+}
+
+fn sanitize_theme_next(next: Option<&str>) -> String {
+    let s = next.unwrap_or("/").trim();
+    if s.starts_with('/') && !s.starts_with("//") && s.len() < 8192 {
+        s.to_string()
+    } else {
+        "/".to_string()
+    }
+}
+
+#[derive(Debug, Deserialize)]
+pub struct ThemeForm {
+    theme: String,
+    next: Option<String>,
+}
+
+/// `POST /theme` — set theme cookie and redirect back (full navigation, no fetch).
+pub async fn post_theme(Form(form): Form<ThemeForm>) -> impl IntoResponse {
+    let theme = normalize_theme(&form.theme);
+    let next = sanitize_theme_next(form.next.as_deref());
+    let loc = HeaderValue::try_from(next.as_str())
+        .unwrap_or_else(|_| HeaderValue::from_static("/"));
+    Response::builder()
+        .status(StatusCode::SEE_OTHER)
+        .header(header::LOCATION, loc)
+        .header(header::SET_COOKIE, theme_cookie_header_value(theme))
+        .body(Body::empty())
+        .expect("theme redirect response")
+}
+
 // Embed CSS files at compile time
 const THEME_DEFAULT_CSS: &str = include_str!("../../static/theme_default.css");
 const THEME_RETRO_CSS: &str = include_str!("../../static/theme_retro.css");
@@ -173,7 +245,9 @@ impl JsQueryBuilder {
     }
 }
 
-pub(super) fn layout(title: &str, view: &str, body: Markup, views: Option<u64>) -> Markup {
+pub(super) fn layout(title: &str, view: &str, body: Markup, views: Option<u64>, theme: &str, theme_next: &str) -> Markup {
+    let theme = normalize_theme(theme);
+    let css_href = format!("/static/theme_{theme}.css");
     html! {
         (DOCTYPE)
         html {
@@ -181,7 +255,20 @@ pub(super) fn layout(title: &str, view: &str, body: Markup, views: Option<u64>)
                 meta charset="utf-8";
                 meta name="viewport" content="width=device-width, initial-scale=1";
                 title { (title) }
-                link rel="stylesheet" href="/static/theme_default.css" id="theme-stylesheet";
+                script { (maud::PreEscaped(r#"
+(function() {
+  try {
+    var ls = localStorage.getItem('slug-theme');
+    if (!ls) return;
+    var m = document.cookie.match(/(?:^|;\s*)slug-theme=([^;]+)/);
+    var c = m ? decodeURIComponent(m[1].replace(/\+/g, ' ')) : '';
+    if (ls === c) { localStorage.removeItem('slug-theme'); return; }
+    document.cookie = 'slug-theme=' + encodeURIComponent(ls) + '; Path=/; SameSite=Lax; Max-Age=31536000';
+    location.reload();
+  } catch (e) {}
+})();
+"#)) }
+                link rel="stylesheet" href=(css_href) id="theme-stylesheet";
                 script src="https://unpkg.com/idiomorph@0.3.0/dist/idiomorph.min.js" {}
             }
             body class=(view) {
@@ -196,32 +283,21 @@ pub(super) fn layout(title: &str, view: &str, body: Markup, views: Option<u64>)
                         input type="range" id="spread-slider" min="0" max="1" step="0.05" value="1";
                     }
                     a id="search-btn" href="/search" { "search" }
-                    div id="theme-switcher" { "theme" }
+                    form id="slug-theme-form" method="post" action="/theme" {
+                        input type="hidden" name="next" value=(theme_next);
+                        select id="theme-select" name="theme" onchange="this.form.submit()" aria-label="Theme" {
+                            @for (val, label) in [("default", "default"), ("retro", "retro"), ("retro_craft", "craft")] {
+                                @if theme == val {
+                                    option value=(val) selected { (label) }
+                                } @else {
+                                    option value=(val) { (label) }
+                                }
+                            }
+                        }
+                    }
                 }
 script { (maud::PreEscaped(r#"
                     (function() {
-                        // Theme switching
-                        const themes = ['default', 'retro', 'retro_craft'];
-                        const themeLabel = { default: 'default', retro: 'retro', retro_craft: 'craft' };
-                        const storedTheme = localStorage.getItem('slug-theme') || 'default';
-                        const switcher = document.getElementById('theme-switcher');
-                        const stylesheet = document.getElementById('theme-stylesheet');
-
-                        function setTheme(name) {
-                            stylesheet.href = `/static/theme_${name}.css`;
-                            localStorage.setItem('slug-theme', name);
-                            switcher.textContent = themeLabel[name] || name;
-                            setTimeout(() => setSpread(parseFloat(slider.value)), 50);
-                        }
-
-                        setTheme(storedTheme);
-
-                        switcher.addEventListener('click', function() {
-                            const current = themes.indexOf(localStorage.getItem('slug-theme') || 'default');
-                            const next = (current + 1) % themes.length;
-                            setTheme(themes[next]);
-                        });
-
                         // Spread control
                         const slider = document.getElementById('spread-slider');
                         const storedSpread = localStorage.getItem('slug-spread');
@@ -245,6 +321,7 @@ script { (maud::PreEscaped(r#"
                             const f = e.target;
                             if (!f || f.tagName !== 'FORM') return;
                             if ((f.method || 'get').toLowerCase() !== 'post') return;
+                            if (f.id === 'slug-theme-form') return;
                             e.preventDefault();
                             const resp = await fetch(f.action, {
                                 method: 'POST',
diff --git a/server/src/html/search.rs b/server/src/html/search.rs
index 0871ddb7a87e3153e2cb6c1f827b46de2c9f0f3b..28ceaa53c3fcac6777311535e95fb771b19438f5 100644
--- a/server/src/html/search.rs
+++ b/server/src/html/search.rs
@@ -1,6 +1,6 @@
 use axum::{
     extract::{Query, State},
-    http::HeaderMap,
+    http::{HeaderMap, Uri},
     response::{Html, IntoResponse},
 };
 use axum_extra::extract::cookie::CookieJar;
@@ -15,7 +15,7 @@ use crate::{
     timeago,
 };
 
-use super::{authorship_address, bc_segment, cli_panel, layout, now_ms};
+use super::{authorship_address, bc_segment, cli_panel, layout, now_ms, theme_from_jar, theme_next_from_uri};
 
 /// Escape HTML special chars for safe injection.
 fn escape_html(s: &str) -> String {
@@ -396,6 +396,7 @@ pub async fn search_page(
     Query(params): Query<SearchQuery>,
     headers: HeaderMap,
     jar: CookieJar,
+    uri: Uri,
 ) -> impl IntoResponse {
     let query = params.q.clone().unwrap_or_default();
     let results = if query.len() >= 2 {
@@ -420,6 +421,8 @@ pub async fn search_page(
             (cli_panel("npx slugsocial search <query>"))
         },
         None,
+        theme_from_jar(&jar),
+        &theme_next_from_uri(&uri),
     );
     Html(page.into_string())
 }
diff --git a/server/src/lib.rs b/server/src/lib.rs
index 43b63293c2a62b9700948767c618cb0614ddf6d9..b9d4b79791ba8dd3a3c26ff777943a2548092de5 100644
--- a/server/src/lib.rs
+++ b/server/src/lib.rs
@@ -33,6 +33,7 @@ pub fn create_app(state: AppState) -> Router {
         .route("/post", post(api::post_web_ingest))
         .route("/post/redact", post(api::post_web_redact))
         .route("/post/check", post(api::check_web_ingest))
+        .route("/theme", post(crate::html::post_theme))
         .route("/sse", get(api::get_html_stream))
         .route("/stream", get(api::get_stream))
         .route("/search", get(crate::html::search_page))
diff --git a/server/src/path_types.rs b/server/src/path_types.rs
index 997597f6659c1ba2092bc5348e393bf7a8fa7ae0..cad58cac7da948f92d6ea2a5587d917ab21d57ea 100644
--- a/server/src/path_types.rs
+++ b/server/src/path_types.rs
@@ -8,6 +8,12 @@
 //!
 //! This module adds lightweight newtypes so code can be explicit about what it
 //! expects without changing core storage formats.
+//!
+//! **Storage vs wire:** [`CanonicalItemUrl`] values are shared across scopes
+//! (`https://slug.social/~/…`); which [`crate::reducer::ContentState`] they live in
+//! is determined by scope, not by embedding the room id in the string. For JSON/RPC
+//! and browser links in a private room, use [`crate::api::helpers::item_path_for_api_in_room`]
+//! so ontology items become `https://slug.social/r/{short}/{slug}/~/…`.
 
 use std::borrow::Borrow;
 use std::fmt;
diff --git a/server/static/theme_default.css b/server/static/theme_default.css
index 2b06b12f3e77c9ed305272fe3ab47a8ad08504df..5e6304bcc36caed8aeda913fd241fc8fb9cf6d25 100644
--- a/server/static/theme_default.css
+++ b/server/static/theme_default.css
@@ -678,7 +678,10 @@ details > summary::-webkit-details-marker { display: none; }
   gap: 6px;
 }
 #spread-slider { accent-color: var(--ui); width: 80px; }
-#theme-switcher {
+#slug-theme-form {
+  display: contents;
+}
+#theme-select {
   background: var(--g4);
   border: var(--bv) solid;
   border-color: var(--hi) var(--lo) var(--lo) var(--hi);
@@ -688,8 +691,8 @@ details > summary::-webkit-details-marker { display: none; }
   padding: 2px 10px;
   user-select: none;
 }
-#theme-switcher:hover  { color: var(--signal); }
-#theme-switcher:active {
+#theme-select:hover  { color: var(--signal); }
+#theme-select:active {
   border-color: var(--lo) var(--hi) var(--hi) var(--lo);
   transform: translate(1px, 1px);
 }
diff --git a/server/static/theme_retro_craft.css b/server/static/theme_retro_craft.css
index 508222443a3bb2f16d3034a07af53a7df37a0314..3fde7e2b77fa4e4f46418927eb0fb0e5cd195c75 100644
--- a/server/static/theme_retro_craft.css
+++ b/server/static/theme_retro_craft.css
@@ -35,7 +35,6 @@ h1, h2, h3 {
   font-weight: 600;
   letter-spacing: 0.14em;
   margin: 1.5rem 0 0.5rem;
-  text-transform: uppercase;
 }
 
 a {
@@ -354,7 +353,10 @@ div.cli-panel {
   accent-color: var(--accent);
   width: 72px;
 }
-#theme-switcher,
+#slug-theme-form {
+  display: contents;
+}
+#theme-select,
 #search-btn,
 a#src-link {
   border: 1px solid var(--line);
@@ -365,7 +367,7 @@ a#src-link {
   padding: 0.25rem 0.6rem;
   text-decoration: none;
 }
-#theme-switcher:hover,
+#theme-select:hover,
 #search-btn:hover,
 a#src-link:hover {
   border-color: var(--accent);


Side B — contributor: tommy-mor
Side B — commit message:
[2bc302c3] refactor

Side B — unified diff (full patch):
diff --git a/server/src/api/ui_html.rs b/server/src/api/ui_html.rs
index 06001212820101e0cc953d3687dea64f85e60787..d2f9769108def7ca2c5857aec8b4319426188a66 100644
--- a/server/src/api/ui_html.rs
+++ b/server/src/api/ui_html.rs
@@ -47,7 +47,7 @@ pub async fn post_ui_html(
             ratio_left,
             ratio_right,
             scope,
-            next,
+            vote_compare,
         } => {
             let parent = parent_from_scope(&scope);
             if let Err(e) = state
@@ -57,14 +57,12 @@ pub async fn post_ui_html(
                 return ui_js_warn(&e).into_response();
             }
             let tree = state.tree.read().await;
-            if !next.trim().is_empty() {
+            if vote_compare {
+                let left = parse_item_param(&a);
+                let right = parse_item_param(&b);
+                let morph = crate::html::vote::vote_recorded_morph(&tree, &parent, &left, &right);
                 drop(tree);
-                return JsBuilder::new()
-                    .raw(&format!(
-                        "window.location.href={};",
-                        js_string_literal(next.trim())
-                    ))
-                    .into_response();
+                return morph.into_response();
             }
             let empty = crate::reducer::NodeState::default();
             let node = tree.get(&parent).unwrap_or(&empty);
@@ -137,7 +135,7 @@ mod tests {
                 ratio_left: 3,
                 ratio_right: 1,
                 scope: String::new(),
-                next: String::new(),
+                vote_compare: false,
             }
         );
     }
diff --git a/server/src/html/mod.rs b/server/src/html/mod.rs
index 61cdbc094819ddedb755572c59456ec0d6617619..cd578a5fea46a9a1d49e238d08a80c2caf18708d 100644
--- a/server/src/html/mod.rs
+++ b/server/src/html/mod.rs
@@ -65,6 +65,15 @@ impl JsBuilder {
         self
     }
 
+    pub(crate) fn morph_inner_selector(mut self, selector: &str, markup: Markup) -> Self {
+        let html = js_string_literal(&markup.into_string());
+        self.snippets.push(format!(
+            "var __el = document.querySelector({sel}); if (__el) {{ Idiomorph.morph(__el, {html}, {{ morphStyle: 'innerHTML' }}); }}",
+            sel = js_string_literal(selector),
+        ));
+        self
+    }
+
     pub(crate) fn raw(mut self, js: &str) -> Self {
         if !js.is_empty() {
             self.snippets.push(js.to_string());
diff --git a/server/src/html/vote.rs b/server/src/html/vote.rs
new file mode 100644
index 0000000000000000000000000000000000000000..89ed621ad861214e147add2062224fc4137ff8ad
--- /dev/null
+++ b/server/src/html/vote.rs
@@ -0,0 +1,306 @@
+//! Pairwise vote UI — `/vote?parent=` with optional `left` / `right`.
+
+use axum::{
+    extract::{Query, State},
+    response::{Html, IntoResponse},
+};
+use maud::{html, Markup};
+use serde::Deserialize;
+
+use crate::{
+    form_template::template_json_compact,
+    html::JsBuilder,
+    pair::{children_of, resolve_pair, suggest_next_pair_in_pool},
+    path_types::ItemId,
+    reducer::{GlobalTree, GroupState, NodeState, VoteData},
+    state::{parse_item_param, AppState},
+    ui_action::UI_RPC_FIELD,
+};
+
+use super::{breadcrumb_path, item_href, layout};
+
+#[derive(Debug, Deserialize)]
+pub struct VoteQuery {
+    pub parent: String,
+    #[serde(default)]
+    pub left: Option<String>,
+    #[serde(default)]
+    pub right: Option<String>,
+}
+
+pub fn vote_href(parent: &ItemId) -> String {
+    format!(
+        "/vote?parent={}",
+        urlencoding::encode(parent.as_str())
+    )
+}
+
+fn vote_compare_href(parent: &ItemId, left: &ItemId, right: &ItemId) -> String {
+    format!(
+        "/vote?parent={}&left={}&right={}",
+        urlencoding::encode(parent.as_str()),
+        urlencoding::encode(left.as_str()),
+        urlencoding::encode(right.as_str()),
+    )
+}
+
+fn display_label(id: &ItemId) -> String {
+    id.segments()
+        .last()
+        .map_or("item".into(), |v| v.to_string())
+}
+
+fn child_title(tree: &GlobalTree, id: &ItemId) -> String {
+    tree.get(id)
+        .and_then(|n| n.data.as_ref())
+        .map(|d| d.title.clone())
+        .unwrap_or_else(|| display_label(id))
+}
+
+fn ratio_pct(ratio_left: i32, ratio_right: i32) -> f64 {
+    let l = ratio_left.max(0) as f64;
+    let r = ratio_right.max(0) as f64;
+    let sum = l + r;
+    if sum <= 0.0 {
+        50.0
+    } else {
+        (l / sum) * 100.0
+    }
+}
+
+fn ratios_for_page(v: &VoteData, page_left: &ItemId, page_right: &ItemId) -> (i32, i32) {
+    match (v.a.as_str(), v.b.as_str()) {
+        (a, b) if a == page_left.as_str() && b == page_right.as_str() => {
+            (v.ratio_left, v.ratio_right)
+        }
+        (a, b) if a == page_right.as_str() && b == page_left.as_str() => {
+            (v.ratio_right, v.ratio_left)
+        }
+        _ => (v.ratio_left, v.ratio_right),
+    }
+}
+
+fn edge_votes(group: &GroupState, left: &ItemId, right: &ItemId) -> Vec<VoteData> {
+    group
+        .recent_votes
+        .iter()
+        .filter(|v| {
+            (v.a.as_str() == left.as_str() && v.b.as_str() == right.as_str())
+                || (v.a.as_str() == right.as_str() && v.b.as_str() == left.as_str())
+        })
+        .cloned()
+        .collect()
+}
+
+fn vote_edge_history(tree: &GlobalTree, group: &GroupState, left: &ItemId, right: &ItemId) -> Markup {
+    let mut votes = edge_votes(group, left, right);
+    votes.sort_by(|a, b| b.ts.cmp(&a.ts));
+    let legend_left = child_title(tree, left);
+    let legend_right = child_title(tree, right);
+    html! {
+        @if votes.is_empty() {
+            p class="muted vote-edge-empty" { "no votes on this pair yet" }
+        } @else {
+            h3 class="vote-edge-history-title" {
+                "votes on this pair"
+                span class="vote-edge-history-axis muted" { " · " (legend_left) " : " (legend_right) }
+            }
+            ul class="vote-edge-history" {
+                @for v in &votes {
+                    @let (r_left, r_right) = ratios_for_page(v, left, right);
+                    @let pct = ratio_pct(r_left, r_right);
+                    li class="vote-edge-history-row" {
+                        div class="vote-edge-meta" {
+                            span class="vote-edge-ratio" { (format!("{}:{}", r_left, r_right)) }
+                        }
+                        div class="ratio-bar vote-edge-bar" aria-hidden="true" {
+                            div class="ratio-left" style={(format!("width: {:.3}%;", pct))} {}
+                            div class="ratio-right" style={(format!("width: {:.3}%;", 100.0 - pct))} {}
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+fn vote_back_nav(parent: &ItemId) -> Markup {
+    html! {
+        div class="vote-compare-nav" {
+            a class="vote-compare-back muted" href=(item_href(parent)) { "← back to " (display_label(parent)) }
+        }
+    }
+}
+
+fn vote_compare_actions(parent: &ItemId, next: Option<&(ItemId, ItemId)>) -> Markup {
+    let next_href = next.map(|(l, r)| vote_compare_href(parent, l, r));
+    html! {
+        div id="vote-compare-actions" class="vote-compare-actions" {
+            button type="submit" class="btn-primary" data-testid="vote-post" { "post vote" }
+            @if let Some(href) = &next_href {
+                a class="btn-secondary vote-compare-next" data-testid="vote-next-pair" href=(href) { "next pair" }
+            } @else {
+                span class="btn-secondary vote-compare-next is-disabled" { "no next pair" }
+            }
+        }
+    }
+}
+
+/// After recording a vote on the compare page: refresh edge history and next-pair link.
+pub(crate) fn vote_recorded_morph(
+    tree: &GlobalTree,
+    parent: &ItemId,
+    left: &ItemId,
+    right: &ItemId,
+) -> JsBuilder {
+    let pool = children_of(tree, parent);
+    let empty = NodeState::default();
+    let group = tree
+        .get(parent)
+        .unwrap_or(&empty)
+        .local_ranking
+        .clone();
+    let edge_history = vote_edge_history(tree, &group, left, right);
+    let next_pair = suggest_next(&group, left, right, &pool);
+    let actions = vote_compare_actions(parent, next_pair.as_ref());
+    JsBuilder::new()
+        .morph_inner_selector("#vote-edge-history-region", edge_history)
+        .morph_selector("#vote-compare-actions", actions)
+}
+
+fn vote_compare_item_card(tree: &GlobalTree, item: &ItemId, side_class: &str) -> Markup {
+    let href = item_href(item);
+    let title = child_title(tree, item);
+    html! {
+        div class=(format!("vote-compare-side {side_class}")) {
+            a class=(format!("vote-compare-item {side_class}")) href=(href) {
+                @if let Some(row) = crate::render::reddit::child_row_markup(tree, item, &href) {
+                    (row)
+                } @else {
+                    strong { (title) }
+                }
+            }
+            @if let Some(node) = tree.get(item) {
+                @if crate::render::reddit::is_reddit_post(item) {
+                    @if let Some(data) = &node.data {
+                        @if let Some(src) = data.image_url.as_ref().or(data.thumb_url.as_ref()) {
+                            figure class="vote-compare-figure" {
+                                img class="vote-compare-image" src=(src) alt="" loading="lazy";
+                            }
+                        }
+                        @if let Some(author) = &data.author {
+                            p class="muted small" { "by " (author) }
+                        }
+                    }
+                } @else if let Some(data) = &node.data {
+                    @if let Some(body) = &data.body_html {
+                        div class="vote-compare-item-body" {
+                            (maud::PreEscaped(body))
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+
+fn suggest_next(group: &GroupState, left: &ItemId, right: &ItemId, pool: &[ItemId]) -> Option<(ItemId, ItemId)> {
+    suggest_next_pair_in_pool(group, pool, Some((left, right)))
+}
+
+pub async fn vote_page(
+    State(state): State<AppState>,
+    Query(q): Query<VoteQuery>,
+) -> impl IntoResponse {
+    let parent = parse_item_param(&q.parent);
+    let left_param = q.left.as_deref().map(parse_item_param);
+    let right_param = q.right.as_deref().map(parse_item_param);
+
+    let tree = state.tree.read().await;
+    let empty = NodeState::default();
+    let parent_node = tree.get(&parent).unwrap_or(&empty);
+
+    let (left, right) = match resolve_pair(
+        &tree,
+        &parent,
+        left_param.as_ref(),
+        right_param.as_ref(),
+    ) {
+        Ok(p) => p,
+        Err(e) => {
+            let (msg, status) = e.status_message();
+            return (status, msg).into_response();
+        }
+    };
+
+    let pool = children_of(&tree, &parent);
+    let group = &parent_node.local_ranking;
+    let next_pair = suggest_next(group, &left, &right, &pool);
+    let edge_history = vote_edge_history(&tree, group, &left, &right);
+
+    let rpc_json = template_json_compact(&serde_json::json!({
+        "action": "record_vote",
+        "a": left.as_str(),
+        "b": right.as_str(),
+        "ratio_left": {"$form:i32": "ratio_left"},
+        "ratio_right": {"$form:i32": "ratio_right"},
+        "scope": parent.as_str(),
+        "vote_compare": true,
+    }))
+    .expect("vote rpc json");
+
+    let title = format!(
+        "vote — {} vs {}",
+        child_title(&tree, &left),
+        child_title(&tree, &right)
+    );
+
+    let body = html! {
+        section class="vote-compare-shell" {
+            h1 { "compare" }
+            (breadcrumb_path(&parent))
+            p class="muted vote-compare-scope" {
+                "ranking children of "
+                a href=(item_href(&parent)) { (child_title(&tree, &parent)) }
+            }
+            div class="vote-compare-pair" {
+                (vote_compare_item_card(&tree, &left, "vote-compare-left"))
+                span class="vote-compare-vs" { "vs" }
+                (vote_compare_item_card(&tree, &right, "vote-compare-right"))
+            }
+            (vote_back_nav(&parent))
+            div id="vote-edge-history-region" {
+                (edge_history)
+            }
+            form id="vote-compare-form" method="POST" action="/ui" {
+                input type="hidden" name=(UI_RPC_FIELD) value=(rpc_json);
+                input type="hidden" name="ratio_left" id="vote-ratio-left" value="50";
+                input type="hidden" name="ratio_right" id="vote-ratio-right" value="50";
+                label class="vote-compare-slider-label" {
+                    span id="vote-slider-left-label" { (child_title(&tree, &left)) }
+                    input type="range" id="vote-preference-slider" min="0" max="100" value="50"
+                        aria-valuemin="0" aria-valuemax="100";
+                    span id="vote-slider-right-label" { (child_title(&tree, &right)) }
+                }
+                (vote_compare_actions(&parent, next_pair.as_ref()))
+            }
+        }
+    };
+
+    drop(tree);
+
+    let path = format!("/vote?parent={}", urlencoding::encode(parent.as_str()));
+    state.views.increment(path.clone());
+    let views = state.views.get_views(&path);
+
+    Html(
+        layout(
+            &title,
+            body,
+            views,
+        )
+        .into_string(),
+    )
+    .into_response()
+}
diff --git a/server/src/pair.rs b/server/src/pair.rs
new file mode 100644
index 0000000000000000000000000000000000000000..606ffa51038a57ffacf335aa48bdb1185f8483fb
--- /dev/null
+++ b/server/src/pair.rs
@@ -0,0 +1,340 @@
+//! Pick two children of a parent scope for pairwise voting.
+//!
+//! Pair selection prefers **bridge** votes — comparisons between items in
+//! different connected components of the voted-pairs graph — so the pool
+//! merges into one ranking group before refining within it.
+
+use rand::seq::SliceRandom;
+use std::collections::{HashMap, HashSet};
+
+use crate::{
+    path_types::ItemId,
+    ranking::connected_components_from_voted_pairs,
+    reducer::{GlobalTree, GroupState},
+};
+
+fn pairs_match(a: &ItemId, b: &ItemId, x: &ItemId, y: &ItemId) -> bool {
+    (a == x && b == y) || (a == y && b == x)
+}
+
+fn pair_is_voted(group: &GroupState, a: &ItemId, b: &ItemId) -> bool {
+    let Some(&ai) = group.item_to_idx.get(a) else {
+        return false;
+    };
+    let Some(&bi) = group.item_to_idx.get(b) else {
+        return false;
+    };
+    let (i, j) = if ai < bi { (ai, bi) } else { (bi, ai) };
+    group.voted_pairs.contains(&(i, j))
+}
+
+/// Component id per pool item: voted-pairs graph components plus one id per
+/// never-voted child.
+fn component_ids(group: &GroupState, pool: &[ItemId]) -> HashMap<ItemId, usize> {
+    let n = group.idx_to_item.len();
+    let (comps, isolates) =
+        connected_components_from_voted_pairs(n, group.voted_pairs.iter().copied());
+
+    let mut out: HashMap<ItemId, usize> = HashMap::new();
+    for (comp_idx, comp) in comps.iter().enumerate() {
+        for &idx in comp {
+            if idx < n {
+                out.insert(group.idx_to_item[idx].clone(), comp_idx);
+            }
+        }
+    }
+    let mut next = comps.len();
+    for &idx in &isolates {
+        if idx < n {
+            out.insert(group.idx_to_item[idx].clone(), next);
+            next += 1;
+        }
+    }
+    for item in pool {
+        out.entry(item.clone()).or_insert_with(|| {
+            let id = next;
+            next += 1;
+            id
+        });
+    }
+    out
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+enum PairPriority {
+    /// Unvoted edge between two components — grows the ranking group.
+    BridgeUnvoted = 0,
+    /// Unvoted edge inside one component — refines order.
+    WithinUnvoted = 1,
+    /// Re-vote across components (rare once merged).
+    BridgeVoted = 2,
+    /// Re-vote within a component.
+    WithinVoted = 3,
+}
+
+fn pair_priority(
+    group: &GroupState,
+    components: &HashMap<ItemId, usize>,
+    a: &ItemId,
+    b: &ItemId,
+) -> PairPriority {
+    let voted = pair_is_voted(group, a, b);
+    let bridge = components.get(a) != components.get(b);
+    match (bridge, voted) {
+        (true, false) => PairPriority::BridgeUnvoted,
+        (false, false) => PairPriority::WithinUnvoted,
+        (true, true) => PairPriority::BridgeVoted,
+        (false, true) => PairPriority::WithinVoted,
+    }
+}
+
+/// All unordered pairs from `pool`, optionally skipping `exclude`.
+fn candidate_pairs(
+    pool: &[ItemId],
+    exclude: Option<(&ItemId, &ItemId)>,
+) -> Vec<(ItemId, ItemId)> {
+    let mut out = Vec::new();
+    for i in 0..pool.len() {
+        for j in (i + 1)..pool.len() {
+            let a = &pool[i];
+            let b = &pool[j];
+            if a == b {
+                continue;
+            }
+            if exclude.is_some_and(|(x, y)| pairs_match(a, b, x, y)) {
+                continue;
+            }
+            out.push((a.clone(), b.clone()));
+        }
+    }
+    out
+}
+
+/// Pick the next pair to vote on within `pool`.
+///
+/// 1. Prefer unvoted **bridge** pairs (connect separate ranking components).
+/// 2. Then unvoted within-component pairs (refinement).
+/// 3. Then already-voted pairs (re-compare).
+pub fn suggest_next_pair_in_pool(
+    group: &GroupState,
+    pool: &[ItemId],
+    exclude: Option<(&ItemId, &ItemId)>,
+) -> Option<(ItemId, ItemId)> {
+    let candidates = candidate_pairs(pool, exclude);
+    if candidates.is_empty() {
+        return None;
+    }
+    let components = component_ids(group, pool);
+    let best = candidates
+        .iter()
+        .map(|(a, b)| (pair_priority(group, &components, a, b), (a, b)))
+        .min_by_key(|(p, _)| *p)?
+        .0;
+    let best_pairs: Vec<(ItemId, ItemId)> = candidates
+        .into_iter()
+        .filter(|(a, b)| pair_priority(group, &components, a, b) == best)
+        .collect();
+    best_pairs.choose(&mut rand::thread_rng()).cloned()
+}
+
+/// Random distinct pair from `children` (legacy pair.rs behavior).
+pub fn random_pair(children: &[ItemId]) -> Option<(ItemId, ItemId)> {
+    if children.len() < 2 {
+        return None;
+    }
+    let left = children.choose(&mut rand::thread_rng())?;
+    let mut right = children.choose(&mut rand::thread_rng())?;
+    let mut guard = 0;
+    while left == right && guard < 32 {
+        right = children.choose(&mut rand::thread_rng())?;
+        guard += 1;
+    }
+    if left == right {
+        return None;
+    }
+    Some((left.clone(), right.clone()))
+}
+
+/// Sorted children of `parent` from the global tree.
+pub fn children_of(tree: &GlobalTree, parent: &ItemId) -> Vec<ItemId> {
+    let Some(node) = tree.get(parent) else {
+        return Vec::new();
+    };
+    let mut children: Vec<ItemId> = node.children.iter().cloned().collect();
+    children.sort_by(|a, b| a.as_str().cmp(b.as_str()));
+    children
+}
+
+/// Resolve a pair to compare under `parent`.
+pub fn resolve_pair(
+    tree: &GlobalTree,
+    parent: &ItemId,
+    left: Option<&ItemId>,
+    right: Option<&ItemId>,
+) -> Result<(ItemId, ItemId), PairError> {
+    let children = children_of(tree, parent);
+    if children.len() < 2 {
+        return Err(PairError::TooFewChildren);
+    }
+    let child_set: HashSet<_> = children.iter().collect();
+
+    match (left, right) {
+        (Some(l), Some(r)) => {
+            if l == r {
+                return Err(PairError::SameItem);
+            }
+            if !child_set.contains(l) || !child_set.contains(r) {
+                return Err(PairError::NotChild);
+            }
+            Ok((l.clone(), r.clone()))
+        }
+        (None, None) => {
+            let group = tree
+                .get(parent)
+                .map(|n| &n.local_ranking)
+                .cloned()
+                .unwrap_or_default();
+            suggest_next_pair_in_pool(&group, &children, None).ok_or(PairError::NoPair)
+        }
+        _ => Err(PairError::IncompletePair),
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum PairError {
+    TooFewChildren,
+    SameItem,
+    NotChild,
+    IncompletePair,
+    NoPair,
+}
+
+impl PairError {
+    pub fn status_message(&self) -> (&'static str, axum::http::StatusCode) {
+        match self {
+            Self::TooFewChildren => (
+                "parent needs at least 2 children to vote",
+                axum::http::StatusCode::BAD_REQUEST,
+            ),
+            Self::SameItem => (
+                "left and right must differ",
+                axum::http::StatusCode::BAD_REQUEST,
+            ),
+            Self::NotChild => (
+                "left and right must be children of parent",
+                axum::http::StatusCode::BAD_REQUEST,
+            ),
+            Self::IncompletePair => (
+                "provide both left and right, or neither",
+                axum::http::StatusCode::BAD_REQUEST,
+            ),
+            Self::NoPair => (
+                "no pair available",
+                axum::http::StatusCode::BAD_REQUEST,
+            ),
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::reducer::{GlobalTree, VoteData};
+
+    fn seed_children(parent: &ItemId, ids: &[&str]) -> GlobalTree {
+        let mut tree = GlobalTree::new();
+        tree.ensure_path(parent);
+        for id in ids {
+            let child = ItemId::parse(id).unwrap();
+            tree.ensure_path(&child);
+            if let Some(p) = tree.nodes.get_mut(parent) {
+                p.children.insert(child);
+            }
+        }
+        tree
+    }
+
+    fn pair_set(pair: &(ItemId, ItemId)) -> HashSet<&str> {
+        [pair.0.as_str(), pair.1.as_str()].into_iter().collect()
+    }
+
+    #[test]
+    fn suggest_prefers_unvoted_pair() {
+        let parent = ItemId::parse("reddit.com/r/rust").unwrap();
+        let mut tree = seed_children(
+            &parent,
+            &[
+                "reddit.com/r/rust/a",
+                "reddit.com/r/rust/b",
+                "reddit.com/r/rust/c",
+            ],
+        );
+        let vote =
+            VoteData::from_recorded(1, "reddit.com/r/rust/a", "reddit.com/r/rust/b", 2, 1).unwrap();
+        tree.apply_vote(&parent, vote);
+        let group = tree.get(&parent).unwrap().local_ranking.clone();
+        let pool = children_of(&tree, &parent);
+        let (l, r) = suggest_next_pair_in_pool(&group, &pool, None).unwrap();
+        let voted_ab = (l.as_str() == "reddit.com/r/rust/a" && r.as_str() == "reddit.com/r/rust/b")
+            || (l.as_str() == "reddit.com/r/rust/b" && r.as_str() == "reddit.com/r/rust/a");
+        assert!(!voted_ab);
+    }
+
+    #[test]
+    fn suggest_bridges_separate_components() {
+        let parent = ItemId::parse("reddit.com/r/rust").unwrap();
+        let mut tree = seed_children(
+            &parent,
+            &[
+                "reddit.com/r/rust/a",
+                "reddit.com/r/rust/b",
+                "reddit.com/r/rust/c",
+                "reddit.com/r/rust/d",
+            ],
+        );
+        let ab = VoteData::from_recorded(1, "reddit.com/r/rust/a", "reddit.com/r/rust/b", 2, 1).unwrap();
+        let cd = VoteData::from_recorded(2, "reddit.com/r/rust/c", "reddit.com/r/rust/d", 2, 1).unwrap();
+        tree.apply_vote(&parent, ab);
+        tree.apply_vote(&parent, cd);
+        let group = tree.get(&parent).unwrap().local_ranking.clone();
+        let pool = children_of(&tree, &parent);
+        let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();
+        let chosen = pair_set(&pair);
+        let from_ab = chosen.contains("reddit.com/r/rust/a") || chosen.contains("reddit.com/r/rust/b");
+        let from_cd = chosen.contains("reddit.com/r/rust/c") || chosen.contains("reddit.com/r/rust/d");
+        assert!(from_ab && from_cd, "expected bridge pair, got {:?}", chosen);
+    }
+
+    #[test]
+    fn suggest_connects_isolate_to_existing_component() {
+        let parent = ItemId::parse("reddit.com/r/rust").unwrap();
+        let mut tree = seed_children(
+            &parent,
+            &[
+                "reddit.com/r/rust/a",
+                "reddit.com/r/rust/b",
+                "reddit.com/r/rust/c",
+            ],
+        );
+        let ab = VoteData::from_recorded(1, "reddit.com/r/rust/a", "reddit.com/r/rust/b", 2, 1).unwrap();
+        tree.apply_vote(&parent, ab);
+        let group = tree.get(&parent).unwrap().local_ranking.clone();
+        let pool = children_of(&tree, &parent);
+        let pair = suggest_next_pair_in_pool(&group, &pool, None).unwrap();
+        let chosen = pair_set(&pair);
+        assert!(chosen.contains("reddit.com/r/rust/c"));
+        assert!(chosen.contains("reddit.com/r/rust/a") || chosen.contains("reddit.com/r/rust/b"));
+    }
+
+    #[test]
+    fn resolve_pair_picks_from_pool() {
+        let parent = ItemId::parse("reddit.com/r/rust").unwrap();
+        let tree = seed_children(&parent, &["reddit.com/r/rust/a", "reddit.com/r/rust/b"]);
+        let pair = resolve_pair(&tree, &parent, None, None).unwrap();
+        let pool: HashSet<_> = ["reddit.com/r/rust/a", "reddit.com/r/rust/b"]
+            .into_iter()
+            .collect();
+        assert!(pool.contains(pair.0.as_str()));
+        assert!(pool.contains(pair.1.as_str()));
+    }
+}
diff --git a/server/src/path_types.rs b/server/src/path_types.rs
index 12dce9888f5cd4e1a0974d12d6468368d0f775b9..a0d1a028b8bd3c5d1c714dea3ec597d1ac39e1bc 100644
--- a/server/src/path_types.rs
+++ b/server/src/path_types.rs
@@ -40,6 +40,22 @@ impl ItemId {
         Self::canonicalize(raw_url).map(Self)
     }
 
+    /// Normalize strings from forms, events, and Reddit imports into the same
+    /// stored id shape (e.g. drop post title slug after comment id).
+    pub fn from_storage(s: &str) -> Option<Self> {
+        let t = s.trim();
+        if t.is_empty() {
+            return None;
+        }
+        if t.contains("://") || t.starts_with("r/") {
+            return Self::from_url(t).or_else(|| Self::parse(t));
+        }
+        if t.starts_with("reddit.com/") && t.contains("/comments/") {
+            return Self::from_url(t).or_else(|| Self::parse(t));
+        }
+        Self::parse(t).or_else(|| Self::from_url(t))
+    }
+
     /// Map legacy scope keys (`""`, `"rust"`) to fractal parent nodes.
     pub fn from_legacy_scope(raw: &str) -> Self {
         let s = raw.trim();
@@ -324,6 +340,12 @@ mod tests {
         assert_eq!(id.as_str(), "reddit.com/r/amitheasshole");
     }
 
+    #[test]
+    fn from_storage_strips_post_title_slug() {
+        let id = ItemId::from_storage("reddit.com/r/rust/comments/aaa/announcing_rust_199").unwrap();
+        assert_eq!(id.as_str(), "reddit.com/r/rust/comments/aaa");
+    }
+
     #[test]
     fn from_browse_uri_strips_prefix() {
         let id = ItemId::from_browse_uri("/~/https://reddit.com/r/rust").unwrap();
diff --git a/server/src/reddit.rs b/server/src/reddit.rs
index 1168ec2afc77c092514eec91b513bac301cbe225..626454e5a2f638734193b5190a2beea286af85b6 100644
--- a/server/src/reddit.rs
+++ b/server/src/reddit.rs
@@ -567,7 +567,7 @@ fn parse_children(_parent: &ItemId, payload: &Value) -> Vec<(ItemId, Value)> {
             _ => continue,
         };
         let path = format!("reddit.com{}", permalink.trim_end_matches('/'));
-        if let Some(id) = ItemId::parse(&path) {
+        if let Some(id) = ItemId::from_storage(&path) {
             out.push((id, child.clone()));
         }
     }
diff --git a/server/src/reducer.rs b/server/src/reducer.rs
index 336e78b77d3ab59361b89af5c9868e13da4ac962..fc23f41137d7df33997afe19c533505c250cc305 100644
--- a/server/src/reducer.rs
+++ b/server/src/reducer.rs
@@ -28,8 +28,8 @@ impl VoteData {
         ratio_left: i32,
         ratio_right: i32,
     ) -> Option<Self> {
-        let a = ItemId::parse(a)?;
-        let b = ItemId::parse(b)?;
+        let a = ItemId::from_storage(a)?;
+        let b = ItemId::from_storage(b)?;
         if a == b {
             return None;
         }
@@ -85,8 +85,8 @@ impl GroupState {
     }
 
     pub fn apply_vote(&mut self, mut vote: VoteData) {
-        vote.a = ItemId::parse(vote.a.as_str()).unwrap_or_else(|| vote.a.clone());
-        vote.b = ItemId::parse(vote.b.as_str()).unwrap_or_else(|| vote.b.clone());
+        vote.a = ItemId::from_storage(vote.a.as_str()).unwrap_or(vote.a.clone());
+        vote.b = ItemId::from_storage(vote.b.as_str()).unwrap_or(vote.b.clone());
         if vote.ratio_left < 0 {
             vote.ratio_left = 0;
         }
diff --git a/server/src/state.rs b/server/src/state.rs
index d238701208a1c708b94a778a6a2e1891a678ecbc..4c3008e73cc74d8483a2064a0a280e73d82a01ec 100644
--- a/server/src/state.rs
+++ b/server/src/state.rs
@@ -18,7 +18,7 @@ pub fn parse_item_param(raw: &str) -> ItemId {
     if s.is_empty() {
         return ItemId::root();
     }
-    ItemId::from_url(s).or_else(|| ItemId::parse(s)).unwrap_or_else(|| ItemId::opaque(s))
+    ItemId::from_storage(s).unwrap_or_else(|| ItemId::opaque(s))
 }
 
 /// Legacy: normalize raw ranking subject into a scope key for old event replay.
diff --git a/server/src/ui_action.rs b/server/src/ui_action.rs
index 53581e1362bfcc5dfb4ae3069c41ea6f7be41437..237411a689fb10ad1b7022ea66aee1969c7507ec 100644
--- a/server/src/ui_action.rs
+++ b/server/src/ui_action.rs
@@ -31,9 +31,9 @@ pub enum HtmlUiAction {
         /// Parent node [`ItemId`] string; empty = tree root.
         #[serde(default)]
         scope: String,
-        /// After vote, navigate here (vote compare page).
+        /// Posted from `/vote` compare UI — morph edge history in place.
         #[serde(default)]
-        next: String,
+        vote_compare: bool,
     },
     /// Parse pasted Reddit URL/path; redirect to subreddit ranking on success.
     ParseQuery {
@@ -98,7 +98,7 @@ mod tests {
                 ratio_left: 60,
                 ratio_right: 40,
                 scope: "parent".into(),
-                next: String::new(),
+                vote_compare: false,
             }
         );
     }
@@ -129,7 +129,7 @@ mod tests {
                 ratio_left: 2,
                 ratio_right: 1,
                 scope: "amitheasshole".into(),
-                next: String::new(),
+                vote_compare: false,
             }
         );
     }
@@ -156,7 +156,7 @@ mod tests {
                 ratio_left: 2,
                 ratio_right: 1,
                 scope: String::new(),
-                next: String::new(),
+                vote_compare: false,
             }
         );
     }
diff --git a/server/static/sorter.css b/server/static/sorter.css
index 3c2cec5cb5094013387147c621d75bd341bc06cc..b95718ce463b200a5667d3014dac2119836a0bef 100644
--- a/server/static/sorter.css
+++ b/server/static/sorter.css
@@ -289,11 +289,27 @@ h1 {
 }
 
 .vote-compare-nav {
+  margin: 1rem 0 0.5rem;
+}
+
+.vote-compare-actions {
   display: flex;
-  justify-content: space-between;
+  flex-wrap: wrap;
   align-items: center;
-  gap: 1rem;
-  margin: 1rem 0;
+  gap: 0.75rem;
+  margin-top: 0.5rem;
+}
+
+.vote-compare-actions .btn-secondary {
+  margin-top: 0;
+  display: inline-block;
+  text-decoration: none;
+  line-height: 1.4;
+}
+
+.vote-compare-actions .vote-compare-next.is-disabled {
+  opacity: 0.6;
+  cursor: default;
 }
 
 .vote-compare-next {
diff --git a/server/static/sorter_ui.js b/server/static/sorter_ui.js
index c8d7c3ef2413399ced7898a7edb3e7a2c8e16163..ab15d27f508cc6f5fbca9d8926fd0ca26d64857b 100644
--- a/server/static/sorter_ui.js
+++ b/server/static/sorter_ui.js
@@ -104,11 +104,10 @@
       if (f.getAttribute('data-navigate') === 'full') return;
       e.preventDefault();
       await postUiForm(f);
-      if (f.id === 'vote-form' || f.id === 'vote-compare-form') {
+      if (f.id === 'vote-form') {
         f.reset();
-        var slider = f.querySelector('#vote-preference-slider');
-        if (slider) slider.value = '50';
-        initVoteSlider();
+        var firstField = f.querySelector('input[type="text"]');
+        if (firstField) firstField.focus();
       }
     });
   }
diff --git a/server/tests/integration_ui.rs b/server/tests/integration_ui.rs
index df7d9ab357531c5146d0b326c149fdaa6b531a4a..56d2db313b313ffce07eff38a8ccdaa2fbb9498f 100644
--- a/server/tests/integration_ui.rs
+++ b/server/tests/integration_ui.rs
@@ -25,6 +25,53 @@ async fn start_test_server() -> (SocketAddr, TempDir) {
     (addr, tmp)
 }
 
+#[tokio::test]
+async fn post_ui_vote_compare_morphs_edge_history() {
+    let (addr, _tmp) = start_test_server().await;
+    let parent = "reddit.com/r/rust";
+    let a = "reddit.com/r/rust/comments/aaa/announcing_rust_199";
+    let b = "reddit.com/r/rust/comments/bbb/what_are_you_working_on";
+
+    let rpc = serde_json::json!({
+        "action": "record_vote",
+        "a": a,
+        "b": b,
+        "ratio_left": {"$form:i32": "ratio_left"},
+        "ratio_right": {"$form:i32": "ratio_right"},
+        "scope": parent,
+        "vote_compare": true,
+    })
+    .to_string();
+    let mut form = HashMap::new();
+    form.insert(UI_RPC_FIELD.to_string(), rpc);
+    form.insert("ratio_left".into(), "70".into());
+    form.insert("ratio_right".into(), "30".into());
+
+    let client = reqwest::Client::new();
+    let body = client
+        .post(format!("http://{addr}/ui"))
+        .form(&form)
+        .send()
+        .await
+        .unwrap()
+        .text()
+        .await
+        .unwrap();
+
+    assert!(
+        body.contains("vote-edge-history"),
+        "expected edge history morph, got: {body}"
+    );
+    assert!(
+        body.contains("70:30"),
+        "expected recorded ratio in morph, got: {body}"
+    );
+    assert!(
+        !body.contains("no votes on this pair yet"),
+        "should not show empty edge history after vote, got: {body}"
+    );
+}
+
 #[tokio::test]
 async fn post_ui_record_vote_morphs_ranking_and_persists() {
     let (addr, tmp) = start_test_server().await;
diff --git a/test/reddit_import.clj b/test/reddit_import.clj
index 45a2a19f20799d77e84d8aa64735ab5e7e45f97c..b476488526252c13fd73bdda76e5201678e4a714 100644
--- a/test/reddit_import.clj
+++ b/test/reddit_import.clj
@@ -2,9 +2,8 @@
   (:require [babashka.process :as process]
             [clojure.java.io :as io]
             [clojure.string :as str]
-            [clojure.test :refer [deftest is testing]])
-  (:import [com.sun.net.httpserver HttpServer HttpHandler HttpExchange]
-           [java.net InetSocketAddress]))
+            [clojure.test :refer [deftest is testing]]
+            [test.support.mock-reddit :as mock-reddit]))
 
 (defn- repo-root []
   (.getCanonicalPath (io/file (System/getProperty "user.dir"))))
@@ -13,29 +12,6 @@
   (with-open [s (java.net.ServerSocket. 0)]
     (.getLocalPort s)))
 
-(defn- start-mock-reddit [port fixtures-dir]
-  (let [about (.getBytes (slurp (io/file fixtures-dir "r_rust_about.json")) "UTF-8")
-        listing (.getBytes (slurp (io/file fixtures-dir "r_rust_listing.json")) "UTF-8")
-        server (HttpServer/create (InetSocketAddress. "127.0.0.1" port) 0)
-        handler
-        (proxy [HttpHandler] []
-          (handle [^HttpExchange exchange]
-            ;; Route by path: `/r/<sub>/about.json` is the subreddit entity,
-            ;; `/r/<sub>.json` is the children listing.
-            (let [path (.getPath (.getRequestURI exchange))
-                  body (if (str/includes? path "/about")
-                         about
-                         listing)]
-              (.sendResponseHeaders exchange 200 (alength body))
-              (let [out (.getResponseBody exchange)]
-                (.write out body)
-                (.close out)))))]
-    (.createContext server "/" handler)
-    (.setExecutor server nil)
-    (.start server)
-    (fn stop []
-      (.stop server 0))))
-
 (defn- wait-health [base-url ms]
   (let [deadline (+ (System/currentTimeMillis) ms)
         url (str base-url "/healthz")]
@@ -100,7 +76,7 @@
 (deftest reddit-fetch-via-mock-api
   (testing "Fetch more queues import; event log stores full payload; page shows title"
     (let [root (repo-root)
-          fixtures (str root "/test/fixtures/reddit")
+          fixtures (mock-reddit/fixtures-dir root)
           data-dir (.getAbsolutePath
                     (doto (io/file (System/getProperty "java.io.tmpdir")
                                    (str "sorter2-reddit-" (System/currentTimeMillis)))
@@ -110,7 +86,7 @@
           reddit-base (str "http://127.0.0.1:" reddit-port)
           app-base (str "http://127.0.0.1:" app-port)
           bin (str root "/target/release/sorter2-server")
-          stop-mock (start-mock-reddit reddit-port fixtures)]
+          stop-mock (mock-reddit/start-mock-reddit reddit-port fixtures)]
       (try
         (is (zero? (:exit (process/shell {:dir root}
                                          "cargo" "build" "--release" "--package" "sorter2-server")))
diff --git a/test/support/mock_reddit.clj b/test/support/mock_reddit.clj
new file mode 100644
index 0000000000000000000000000000000000000000..5efa92db3e1f79b8f423a2f1adcbda959123c1ad
--- /dev/null
+++ b/test/support/mock_reddit.clj
@@ -0,0 +1,35 @@
+(ns test.support.mock-reddit
+  "In-process HTTP stub for Reddit API fixtures (`test/fixtures/reddit/`)."
+  (:require [clojure.java.io :as io]
+            [clojure.string :as str])
+  (:import [com.sun.net.httpserver HttpServer HttpHandler HttpExchange]
+           [java.net InetSocketAddress]))
+
+(defn fixtures-dir
+  ([] (fixtures-dir (System/getProperty "user.dir")))
+  ([root] (str root "/test/fixtures/reddit")))
+
+(defn start-mock-reddit
+  "Start a mock Reddit API on `port`. Returns a zero-arg `stop` function."
+  ([port] (start-mock-reddit port (fixtures-dir)))
+  ([port dir]
+   (let [about (.getBytes (slurp (io/file dir "r_rust_about.json")) "UTF-8")
+         listing (.getBytes (slurp (io/file dir "r_rust_listing.json")) "UTF-8")
+         server (HttpServer/create (InetSocketAddress. "127.0.0.1" port) 0)
+         handler
+         (proxy [HttpHandler] []
+           (handle [^HttpExchange exchange]
+             ;; `/r/<sub>/about.json` → subreddit entity; `/r/<sub>.json` → listing.
+             (let [path (.getPath (.getRequestURI exchange))
+                   body (if (str/includes? path "/about")
+                          about
+                          listing)]
+               (.sendResponseHeaders exchange 200 (alength body))
+               (let [out (.getResponseBody exchange)]
+                 (.write out body)
+                 (.close out)))))]
+     (.createContext server "/" handler)
+     (.setExecutor server nil)
+     (.start server)
+     (fn stop []
+       (.stop server 0)))))
diff --git a/test/vote_compare.clj b/test/vote_compare.clj
new file mode 100644
index 0000000000000000000000000000000000000000..fbc00281e466a1ba0833193c7b96fa30aeb45a5c
--- /dev/null
+++ b/test/vote_compare.clj
@@ -0,0 +1,101 @@
+(ns test.vote-compare
+  (:require [babashka.process :as process]
+            [clojure.java.io :as io]
+            [clojure.string :as str]
+            [clojure.test :refer [deftest is testing]]
+            [com.blockether.spel.core :as core]
+            [com.blockether.spel.locator :as loc]
+            [com.blockether.spel.page :as page]
+            [test.support.mock-reddit :as mock-reddit])
+  (:import [java.net URLEncoder]))
+
+(defn- repo-root []
+  (.getCanonicalPath (io/file (System/getProperty "user.dir"))))
+
+(defn- pick-port []
+  (with-open [s (java.net.ServerSocket. 0)]
+    (.getLocalPort s)))
+
+(defn- wait-health [base-url ms]
+  (let [deadline (+ (System/currentTimeMillis) ms)
+        url (str base-url "/healthz")]
+    (loop []
+      (let [resp (try
+                   (process/shell {:out :string :err :string}
+                                  "curl" "-sf" url)
+                   (catch Exception _ nil))]
+        (if (and resp (zero? (:exit resp)) (= "ok" (str/trim (:out resp ""))))
+          true
+          (if (< (System/currentTimeMillis) deadline)
+            (do (Thread/sleep 200) (recur))
+            false))))))
+
+(defn- curl-fetch-children [base item]
+  (process/shell {:out :string :err :string}
+                 "curl" "-sfN" "--max-time" "20"
+                 "-X" "POST" (str base "/ui")
+                 "--data-urlencode"
+                 (str "__rpc__={\"action\":\"fetch_entity\",\"item\":\"" item
+                      "\",\"kind\":\"children\"}")))
+
+(defn- vote-page-url [base parent]
+  (str base "/vote?parent="
+       (URLEncoder/encode parent "UTF-8")))
+
+(deftest vote-compare-shows-recorded-vote-after-post
+  (testing "post vote on /vote morphs edge history (mock Reddit children seeded)"
+    (let [root (repo-root)
+          fixtures (mock-reddit/fixtures-dir root)
+          data-dir (.getAbsolutePath
+                    (doto (io/file (System/getProperty "java.io.tmpdir")
+                                   (str "sorter2-vote-" (System/currentTimeMillis)))
+                      (.mkdirs)))
+          reddit-port (pick-port)
+          app-port (pick-port)
+          reddit-base (str "http://127.0.0.1:" reddit-port)
+          app-base (str "http://127.0.0.1:" app-port)
+          bin (str root "/target/release/sorter2-server")
+          stop-mock (mock-reddit/start-mock-reddit reddit-port fixtures)]
+      (try
+        (is (zero? (:exit (process/shell {:dir root}
+                                         "cargo" "build" "--release" "--package" "sorter2-server")))
+            "release build succeeds")
+        (let [proc (process/process {:dir root
+                                     :env (into (into {} (System/getenv))
+                                                {"SORTER2_SKIP_DOTENV" "1"
+                                                 "SORTER2_DATA_DIR" data-dir
+                                                 "SORTER2_EVENT_LOG" (str data-dir "/events.jsonl")
+                                                 "PORT" (str app-port)
+                                                 "REDDIT_API_BASE" reddit-base
+                                                 "REDDIT_OAUTH_BASE" reddit-base
+                                                 "REDDIT_CLIENT_ID" ""
+                                                 "REDDIT_CLIENT_SECRET" ""
+                                                 "REDDIT_APP_ID" ""
+                                                 "REDDIT_APP_SECRET" ""})
+                                     :out :string
+                                     :err :string}
+                                    bin)]
+          (try
+            (is (wait-health app-base 20000) "app healthz")
+            (let [fetch (curl-fetch-children app-base "reddit.com/r/rust")]
+              (is (zero? (:exit fetch)) "fetch posts via mock Reddit")
+              (is (str/includes? (:out fetch) "Idiomorph.morph")))
+            (core/with-testing-page [pg]
+              (page/navigate pg (vote-page-url app-base "reddit.com/r/rust"))
+              (page/wait-for-selector pg "#vote-compare-form")
+              (let [before (loc/text-content (page/locator pg "#vote-edge-history-region"))]
+                (is (str/includes? before "no votes on this pair yet")
+                    "empty edge history before first vote"))
+              (loc/click (page/get-by-test-id pg "vote-post"))
+              (page/wait-for-selector pg ".vote-edge-history-title")
+              (let [after (loc/text-content (page/locator pg "#vote-edge-history-region"))]
+                (is (str/includes? after "votes on this pair")
+                    "shows edge history title after vote")
+                (is (str/includes? after "50:50")
+                    "shows submitted ratio after vote")
+                (is (not (str/includes? after "no votes on this pair yet"))
+                    "does not revert to empty edge history")))
+            (finally
+              (process/destroy proc))))
+        (finally
+          (stop-mock))))))