fix(ui): adopt Source Serif 4 for AI prose reading register (#140)

* feat(ui): adopt Source Serif 4 for AI prose reading register

Signed-off-by: Logan Nguyen <lg.131.dev@gmail.com>

* fix(ui): adopt Source Serif 4 for AI prose reading register

Signed-off-by: Logan Nguyen <lg.131.dev@gmail.com>

---------

Signed-off-by: Logan Nguyen <lg.131.dev@gmail.com>

Author: quiet-node

bun.lock

@@ -38,7 +38,8 @@
     "validate-build": "bun run lint && bun run format:check && bun run typecheck && bun run build:all"
   },
   "dependencies": {
-    "@tauri-apps/api": "^2.10.1",
+    "@fontsource/source-serif-4": "^5.2.9",
+    "@tauri-apps/api": "^2.11.0",
     "framer-motion": "^12.38.0",
     "react": "^19.2.4",
     "react-dom": "^19.2.4",

package.json

@@ -2,6 +2,10 @@
 @source "../node_modules/streamdown/dist";
 @import 'streamdown/styles.css';
 
+/* Source Serif 4 reading face for AI prose. Chrome stays Inter. */
+@import '@fontsource/source-serif-4/400.css';
+@import '@fontsource/source-serif-4/400-italic.css';
+
 @theme {
   --font-sans:
     'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
@@ -185,6 +189,18 @@ body {
   display: none;
 }
 
+/* AI prose reading face: serif body, warm cream, looser leading. Scoped to
+ * .markdown-body so UI chrome (labels, buttons, search trace) stays Inter.
+ * User bubble renders via renderUserContent, not MarkdownRenderer.
+ */
+.markdown-body {
+  font-family: 'Source Serif 4', Charter, 'Iowan Old Style', Georgia, serif;
+  color: #efe3cc;
+  font-size: 15.5px;
+  line-height: 1.65;
+  letter-spacing: 0.3px;
+}
+
 /* ─── Markdown Body: Prose Defaults ───
  * Tailwind's preflight resets list-style to none globally. Streamdown adds no
  * list CSS of its own, so <ul>/<ol> inside .markdown-body lose their markers.