diff --git a/static/css/app.css b/static/css/app.css
index 94c8723..9418cda 100644
--- a/static/css/app.css
+++ b/static/css/app.css
@@ -2,6 +2,42 @@
    diora — dark radio player theme
    ========================================================= */
 
+/* Self-hosted (no external request, works offline via the service worker's
+   app-shell cache) — variable font covering weight 200-900 in one file per
+   style/subset. Latin + Latin Extended only (covers German/English text). */
+@font-face {
+  font-family: 'Source Serif 4';
+  font-style: normal;
+  font-weight: 200 900;
+  font-display: swap;
+  src: url('/static/fonts/SourceSerif4-normal-latin.woff2') format('woff2');
+  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
+}
+@font-face {
+  font-family: 'Source Serif 4';
+  font-style: normal;
+  font-weight: 200 900;
+  font-display: swap;
+  src: url('/static/fonts/SourceSerif4-normal-latin-ext.woff2') format('woff2');
+  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
+}
+@font-face {
+  font-family: 'Source Serif 4';
+  font-style: italic;
+  font-weight: 200 900;
+  font-display: swap;
+  src: url('/static/fonts/SourceSerif4-italic-latin.woff2') format('woff2');
+  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
+}
+@font-face {
+  font-family: 'Source Serif 4';
+  font-style: italic;
+  font-weight: 200 900;
+  font-display: swap;
+  src: url('/static/fonts/SourceSerif4-italic-latin-ext.woff2') format('woff2');
+  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
+}
+
 *, *::before, *::after {
   box-sizing: border-box;
   margin: 0;
@@ -1942,7 +1978,7 @@ body.dnd-mode .timer-display {
   position: relative;
   padding: 24px 16px;
   line-height: 1.8;
-  font-family: Georgia, 'Times New Roman', serif;
+  font-family: 'Source Serif 4', Georgia, 'Times New Roman', serif;
   font-size: 16px;
   font-weight: 400;
 }
diff --git a/static/fonts/SourceSerif4-italic-latin-ext.woff2 b/static/fonts/SourceSerif4-italic-latin-ext.woff2
new file mode 100644
index 0000000..61c767d
Binary files /dev/null and b/static/fonts/SourceSerif4-italic-latin-ext.woff2 differ
diff --git a/static/fonts/SourceSerif4-italic-latin.woff2 b/static/fonts/SourceSerif4-italic-latin.woff2
new file mode 100644
index 0000000..26f2a43
Binary files /dev/null and b/static/fonts/SourceSerif4-italic-latin.woff2 differ
diff --git a/static/fonts/SourceSerif4-normal-latin-ext.woff2 b/static/fonts/SourceSerif4-normal-latin-ext.woff2
new file mode 100644
index 0000000..fada8d3
Binary files /dev/null and b/static/fonts/SourceSerif4-normal-latin-ext.woff2 differ
diff --git a/static/fonts/SourceSerif4-normal-latin.woff2 b/static/fonts/SourceSerif4-normal-latin.woff2
new file mode 100644
index 0000000..b98e6b5
Binary files /dev/null and b/static/fonts/SourceSerif4-normal-latin.woff2 differ
diff --git a/static/js/app.js b/static/js/app.js
index fd3cf0f..ff4f1d6 100644
--- a/static/js/app.js
+++ b/static/js/app.js
@@ -4993,7 +4993,7 @@ function applyReaderSettings(isPdf) {
     contentEl.style.lineHeight = readerSettings.lineHeight;
     contentEl.style.setProperty('--reader-max-width', readerSettings.maxWidth + 'ch');
     const fontMap = {
-      serif:    "Georgia, 'Times New Roman', serif",
+      serif:    "'Source Serif 4', Georgia, 'Times New Roman', serif",
       sans:     'system-ui, -apple-system, sans-serif',
       humanist: 'Verdana, Geneva, sans-serif',
       mono:     "'Courier New', monospace",
diff --git a/static/js/sw.js b/static/js/sw.js
index 0e6b7b3..72ac2ca 100644
--- a/static/js/sw.js
+++ b/static/js/sw.js
@@ -2,12 +2,16 @@
  * diora service worker — caches the app shell for offline use.
  */
 
-const CACHE = 'diora-v43';
+const CACHE = 'diora-v44';
 const PODCAST_CACHE = 'diora-podcast-v1';
 const SHELL = [
   '/static/css/app.css',
   '/static/js/app.js',
   '/static/manifest.json',
+  '/static/fonts/SourceSerif4-normal-latin.woff2',
+  '/static/fonts/SourceSerif4-normal-latin-ext.woff2',
+  '/static/fonts/SourceSerif4-italic-latin.woff2',
+  '/static/fonts/SourceSerif4-italic-latin-ext.woff2',
 ];
 
 // Install: pre-cache the app shell