You are ranking individual git commits to an open source project.
Compare these two commits. Decide which commit contributed more.
Return ONLY a JSON object: {"winner": "A" or "B", "ratio": "N:M", "explanation": "..."}

Side A — contributor: tommy-mor
Side A — commit message:
[2e4be477] format

Side A — unified diff (full patch):
diff --git a/server/src/html/garden.rs b/server/src/html/garden.rs
index 76ba96e45c9e16291a6ccd8096fdd01b274c1560..2d5fcd903fe8f56800ad2c5564b704bd25f9b18d 100644
--- a/server/src/html/garden.rs
+++ b/server/src/html/garden.rs
@@ -9,30 +9,28 @@ use serde::Deserialize;
 use serde_json::json;
 use std::collections::HashSet;
 
-use base64::{engine::general_purpose::URL_SAFE_NO_PAD as B64_ENGINE, Engine as _};
+use base64::{Engine as _, engine::general_purpose::URL_SAFE_NO_PAD as B64_ENGINE};
 
 use crate::{
     api::optional_principal,
     canonical_path::{canonicalize_item, canonicalize_tag},
-    form_template::template_json_compact,
-    html::{
-        ui_action::UI_RPC_FIELD,
-        user_can_post_room,
-        JsBuilder,
-    },
     events::ThreadCapability,
+    form_template::template_json_compact,
+    html::{JsBuilder, ui_action::UI_RPC_FIELD, user_can_post_room},
     path_types::ItemId,
-    reducer::{scope_from_room_wire, ContentState, ReducerState, ScopeId},
-    scope_rank::{build_children_rankings, ChildrenRankings},
+    reducer::{ContentState, ReducerState, ScopeId, scope_from_room_wire},
+    scope_rank::{ChildrenRankings, build_children_rankings},
     state::AppState,
     timeago,
 };
 
 use super::{
-    bc_path, bc_path_external, bc_segment, cli_panel, layout, layout_full_bleed_chromeless, now_ms,
-    ratio_pct, render_linkified_with_embeds_in_scope, theme_from_jar, theme_next_from_uri,
+    bc_path, bc_path_external, bc_segment,
     breadcrumb_path::{ExternalOntologyPath, OntologyPath},
-    forum::{ingest_entry_markup, ThreadNav},
+    cli_panel,
+    forum::{ThreadNav, ingest_entry_markup},
+    layout, layout_full_bleed_chromeless, now_ms, ratio_pct, render_linkified_with_embeds_in_scope,
+    theme_from_jar, theme_next_from_uri,
 };
 
 /// `GET /vote/compare` — pairs `left` / `right` query params with optional `thread`.
@@ -90,7 +88,11 @@ fn canonical_edge_items(a: &ItemId, b: &ItemId) -> (ItemId, ItemId) {
 }
 
 /// All votes whose endpoints are exactly this unordered pair (unsorted).
-fn edge_vote_entries_for_pair(content: &ContentState, a: &ItemId, b: &ItemId) -> Vec<crate::reducer::VoteData> {
+fn edge_vote_entries_for_pair(
+    content: &ContentState,
+    a: &ItemId,
+    b: &ItemId,
+) -> Vec<crate::reducer::VoteData> {
     let (lo, hi) = canonical_edge_items(a, b);
     let lo_s = lo.as_str();
     let hi_s = hi.as_str();
@@ -107,7 +109,11 @@ fn edge_vote_entries_for_pair(content: &ContentState, a: &ItemId, b: &ItemId) ->
         .collect()
 }
 
-fn ratios_for_compare_page(v: &crate::reducer::VoteData, page_left: &ItemId, page_right: &ItemId) -> (i32, i32) {
+fn ratios_for_compare_page(
+    v: &crate::reducer::VoteData,
+    page_left: &ItemId,
+    page_right: &ItemId,
+) -> (i32, i32) {
     let pl = page_left.as_str();
     let pr = page_right.as_str();
     match (v.a.as_str(), v.b.as_str()) {
@@ -121,11 +127,7 @@ fn left_share_normalized(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 {
-        0.5
-    } else {
-        l / sum
-    }
+    if sum <= 0.0 { 0.5 } else { l / sum }
 }
 
 /// Stronger preference for **`page_left` first**; ties **newer first**.
@@ -177,11 +179,7 @@ fn vote_thread_tags_for_pair(content: &ContentState, a: &ItemId, b: &ItemId) ->
     v.into_iter().map(|t| canonicalize_tag(&t)).collect()
 }
 
-fn vote_edge_history_markup(
-    content: &ContentState,
-    left: &ItemId,
-    right: &ItemId,
-) -> maud::Markup {
+fn vote_edge_history_markup(content: &ContentState, left: &ItemId, right: &ItemId) -> maud::Markup {
     let votes = edge_vote_entries_for_pair(content, left, right);
     let votes = sort_votes_for_compare_display(votes, left, right);
     let legend_left = item_display_path(left.as_str());
@@ -276,7 +274,12 @@ fn item_code_label(item: &str) -> String {
     item_display_path(item)
 }
 
-fn vote_compare_href(nav: &ThreadNav, left: &ItemId, right: &ItemId, thread_override: Option<&str>) -> String {
+fn vote_compare_href(
+    nav: &ThreadNav,
+    left: &ItemId,
+    right: &ItemId,
+    thread_override: Option<&str>,
+) -> String {
     let left_q = urlencoding::encode(left.as_str());
     let right_q = urlencoding::encode(right.as_str());
     let base = format!(
@@ -299,7 +302,8 @@ fn ont_pin_vote_controls(
     next_path: &str,
 ) -> maud::Markup {
     let room_wire = nav.room_wire.clone();
-    let current = ItemId::parse(current_storage).unwrap_or_else(|| ItemId::opaque(current_storage.to_string()));
+    let current = ItemId::parse(current_storage)
+        .unwrap_or_else(|| ItemId::opaque(current_storage.to_string()));
     let pin_matches_scope = pinned_room_and_item
         .map(|(r, _)| r == nav.room_wire.as_str())
         .unwrap_or(false);
@@ -307,26 +311,22 @@ fn ont_pin_vote_controls(
         .filter(|_| pin_matches_scope)
         .map(|(_, i)| i);
 
-    let pin_rpc = template_json_compact(
-        &json!({
-            "action": "set_garden_pin",
-            "clear": false,
-            "room_wire": room_wire,
-            "item_storage": current.as_str(),
-            "next": next_path,
-            "form_action": "/ui",
-        }),
-    )
+    let pin_rpc = template_json_compact(&json!({
+        "action": "set_garden_pin",
+        "clear": false,
+        "room_wire": room_wire,
+        "item_storage": current.as_str(),
+        "next": next_path,
+        "form_action": "/ui",
+    }))
     .expect("pin rpc json");
-    let unpin_rpc = template_json_compact(
-        &json!({
-            "action": "set_garden_pin",
-            "clear": true,
-            "room_wire": "",
-            "next": next_path,
-            "form_action": "/ui",
-        }),
-    )
+    let unpin_rpc = template_json_compact(&json!({
+        "action": "set_garden_pin",
+        "clear": true,
+        "room_wire": "",
+        "next": next_path,
+        "form_action": "/ui",
+    }))
     .expect("unpin rpc json");
 
     html! {
@@ -497,9 +497,9 @@ fn room_scope_has_garden_content(reduced: &ReducerState, nav: &ThreadNav) -> boo
 fn content_for_garden_view<'a>(reduced: &'a ReducerState, scope: &ScopeId) -> &'a ContentState {
     match scope {
         ScopeId::Public => reduced.public(),
-        ScopeId::Room(_) => reduced.content_for_scope(scope).expect(
-            "room garden only renders after room_scope_has_garden_content returned true",
-        ),
+        ScopeId::Room(_) => reduced
+            .content_for_scope(scope)
+            .expect("room garden only renders after room_scope_has_garden_content returned true"),
     }
 }
 
@@ -723,10 +723,8 @@ pub async fn room_external_garden_index(
     }
     let ext_path = ExternalOntologyPath::from_input("");
     let parent = ItemId::parse("https://.").unwrap();
-    let child_rankings = build_children_rankings(
-        content_for_garden_view(&reduced, &nav.scope()),
-        &parent,
-    );
+    let child_rankings =
+        build_children_rankings(content_for_garden_view(&reduced, &nav.scope()), &parent);
     drop(reduced);
 
     let page = layout(
@@ -953,48 +951,74 @@ fn build_rank_history(
         None => return vec![],
         Some(e) => e,
     };
-    entries.iter().map(|e| {
-        // Resolve caused_by: votes from this ingest that directly touched this item.
-        let caused_by: Vec<crate::reducer::VoteData> = reduced.ingests_by_id
-            .get(&e.post_id)
-            .and_then(|ing| crate::dsl::parse_full(&ing.raw).ok())
-            .map(|doc| {
-                doc.statements.into_iter().filter_map(|s| {
-                    if let crate::dsl::Stmt::Vote { item1, item2, ratio_left, ratio_right, explanation } = s {
-                        let a_str = crate::canonical_path::canonicalize_item(&item1);
-                        let b_str = crate::canonical_path::canonicalize_item(&item2);
-                        if a_str == item || b_str == item {
-                            Some(crate::reducer::VoteData {
-                                ts: e.ts,
-                                a: ItemId::parse(&a_str).unwrap_or_else(|| ItemId::opaque(a_str)),
-                                b: ItemId::parse(&b_str).unwrap_or_else(|| ItemId::opaque(b_str)),
-                                ratio_left, ratio_right,
-                                body: explanation,
-                                principal: reduced.ingests_by_id.get(&e.post_id)
-                                    .map(|ing| ing.principal.clone())
-                                    .unwrap_or_default(),
-                                delegate: reduced.ingests_by_id.get(&e.post_id).and_then(|ing| ing.delegate.clone()),
-                                thread_tag: e.thread.clone(),
-                            })
-                        } else { None }
-                    } else { None }
-                }).collect()
-            })
-            .unwrap_or_default();
-
-        let thread_post_index =
-            reduced.thread_post_index_chronological(scope, &e.thread, &e.post_id);
-
-        RankHistoryEntryView {
-            ts: e.ts,
-            scope_rank: e.scope_rank,
-            scope_total: e.scope_total,
-            scope_rank_delta: e.scope_rank_delta,
-            thread: e.thread.clone(),
-            thread_post_index,
-            caused_by,
-        }
-    }).collect()
+    entries
+        .iter()
+        .map(|e| {
+            // Resolve caused_by: votes from this ingest that directly touched this item.
+            let caused_by: Vec<crate::reducer::VoteData> = reduced
+                .ingests_by_id
+                .get(&e.post_id)
+                .and_then(|ing| crate::dsl::parse_full(&ing.raw).ok())
+                .map(|doc| {
+                    doc.statements
+                        .into_iter()
+                        .filter_map(|s| {
+                            if let crate::dsl::Stmt::Vote {
+                                item1,
+                                item2,
+                                ratio_left,
+                                ratio_right,
+                                explanation,
+                            } = s
+                            {
+                                let a_str = crate::canonical_path::canonicalize_item(&item1);
+                                let b_str = crate::canonical_path::canonicalize_item(&item2);
+                                if a_str == item || b_str == item {
+                                    Some(crate::reducer::VoteData {
+                                        ts: e.ts,
+                                        a: ItemId::parse(&a_str)
+                                            .unwrap_or_else(|| ItemId::opaque(a_str)),
+                                        b: ItemId::parse(&b_str)
+                                            .unwrap_or_else(|| ItemId::opaque(b_str)),
+                                        ratio_left,
+                                        ratio_right,
+                                        body: explanation,
+                                        principal: reduced
+                                            .ingests_by_id
+                                            .get(&e.post_id)
+                                            .map(|ing| ing.principal.clone())
+                                            .unwrap_or_default(),
+                                        delegate: reduced
+                                            .ingests_by_id
+                                            .get(&e.post_id)
+                                            .and_then(|ing| ing.delegate.clone()),
+                                        thread_tag: e.thread.clone(),
+                                    })
+                                } else {
+                                    None
+                                }
+                            } else {
+                                None
+                            }
+                        })
+                        .collect()
+                })
+                .unwrap_or_default();
+
+            let thread_post_index =
+                reduced.thread_post_index_chronological(scope, &e.thread, &e.post_id);
+
+            RankHistoryEntryView {
+                ts: e.ts,
+                scope_rank: e.scope_rank,
+                scope_total: e.scope_total,
+                scope_rank_delta: e.scope_rank_delta,
+                thread: e.thread.clone(),
+                thread_post_index,
+                caused_by,
+            }
+        })
+        .collect()
 }
 
 fn build_item_page_view_model(
@@ -1301,23 +1325,28 @@ async fn vote_compare_inner(
     let edge_history = vote_edge_history_markup(content, &left, &right);
     drop(reduced);
 
-    let title = format!("vote — {} vs {}", item_display_path(left.as_str()), item_display_path(right.as_str()));
-    let next_path = uri.path_and_query().map(|pq| pq.as_str().to_string()).unwrap_or_else(|| "/vote/compare".into());
-
-    let rpc_json = template_json_compact(
-        &json!({
-            "action": "vote_compare_post",
-            "room": nav.room_wire,
-            "thread_tag": {"$form": "thread_tag"},
-            "left_item": left.as_str(),
-            "right_item": right.as_str(),
-            "ratio_left": {"$form": "ratio_left"},
-            "ratio_right": {"$form": "ratio_right"},
-            "explanation": {"$form": "explanation"},
-            "next": next_path,
-            "form_action": "/ui",
-        }),
-    )
+    let title = format!(
+        "vote — {} vs {}",
+        item_display_path(left.as_str()),
+        item_display_path(right.as_str())
+    );
+    let next_path = uri
+        .path_and_query()
+        .map(|pq| pq.as_str().to_string())
+        .unwrap_or_else(|| "/vote/compare".into());
+
+    let rpc_json = template_json_compact(&json!({
+        "action": "vote_compare_post",
+        "room": nav.room_wire,
+        "thread_tag": {"$form": "thread_tag"},
+        "left_item": left.as_str(),
+        "right_item": right.as_str(),
+        "ratio_left": {"$form": "ratio_left"},
+        "ratio_right": {"$form": "ratio_right"},
+        "explanation": {"$form": "explanation"},
+        "next": next_path,
+        "form_action": "/ui",
+    }))
     .expect("vote compare rpc json");
 
     let body = html! {
@@ -1532,11 +1561,23 @@ mod tests {
             .iter()
             .map(|r| r.item.as_str())
             .collect();
-        assert_eq!(names, vec!["https://slug.social/~/topic/a", "https://slug.social/~/topic/b"]);
+        assert_eq!(
+            names,
+            vec![
+                "https://slug.social/~/topic/a",
+                "https://slug.social/~/topic/b"
+            ]
+        );
         use crate::path_types::ItemId;
         assert!(
-            model.child_rankings.unranked_items.contains(&ItemId::parse("https://slug.social/~/topic/kid1").unwrap())
-                || model.child_rankings.unranked_items.contains(&ItemId::parse("https://slug.social/~/topic/kid2").unwrap())
+            model
+                .child_rankings
+                .unranked_items
+                .contains(&ItemId::parse("https://slug.social/~/topic/kid1").unwrap())
+                || model
+                    .child_rankings
+                    .unranked_items
+                    .contains(&ItemId::parse("https://slug.social/~/topic/kid2").unwrap())
         );
     }
 
@@ -1609,11 +1650,8 @@ mod tests {
             1,
             "@00000000-0000-0000-0000-000000000000:test:local/test\n~/x {x}\n",
         );
-        let model = build_item_page_view_model(
-            &reduced,
-            &ScopeId::Public,
-            "https://slug.social/~/",
-        );
+        let model =
+            build_item_page_view_model(&reduced, &ScopeId::Public, "https://slug.social/~/");
         assert_eq!(model.child_rankings.unranked_items.len(), 1);
         assert_eq!(
             model.child_rankings.unranked_items[0].as_str(),


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

Side B — 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);