diff --git a/frontend/app.js b/frontend/app.js
index b934e9b..45003f2 100755
--- a/frontend/app.js
+++ b/frontend/app.js
@@ -495,6 +495,9 @@ const Player = {
       navigator.mediaSession.setActionHandler('seekbackward', (d) => Player.seek(Math.max(0, Player.master.currentTime - (d.seekOffset || 10))));
       navigator.mediaSession.setActionHandler('seekforward', (d) => Player.seek(Player.master.currentTime + (d.seekOffset || 10)));
     }
+    // In portrait PWA mode, scroll the player into view so it's immediately
+    // visible without the user having to swipe up manually.
+    scrollPlayerIntoViewPortrait();
     // Restore A-B markers and load related (non-blocking)
     restoreAbMarkers();
     loadRelated();
@@ -1976,6 +1979,52 @@ function showModal(title, bodyNode, actions) {
 }
 function closeModal() { $('modal').classList.add('hidden'); }
 
+// ============================================================================
+// Portrait PWA detection & behavioral layer
+// Mirrors the CSS media query: (display-mode: standalone) and (orientation: portrait)
+// The JS layer adds:
+//   • A `portrait-pwa` class on .app for any JS-driven conditional logic.
+//   • Auto-close the sidebar when rotating into portrait-standalone mode.
+//   • Auto-scroll the player into view when a video starts in portrait mode.
+// ============================================================================
+const _portraitPwaMQ = window.matchMedia
+  ? window.matchMedia('(display-mode: standalone) and (orientation: portrait)')
+  : { matches: false, addEventListener: () => {} };
+
+function isPortraitPWA() {
+  return _portraitPwaMQ.matches;
+}
+
+function applyPortraitPwaClass() {
+  const app = document.querySelector('.app');
+  if (!app) return;
+  if (isPortraitPWA()) {
+    app.classList.add('portrait-pwa');
+  } else {
+    app.classList.remove('portrait-pwa');
+  }
+}
+
+// Scroll the player pane to the top of the scrollable .body so it's visible.
+// Only fires when in portrait-standalone mode where .body is the scroll root.
+function scrollPlayerIntoViewPortrait() {
+  if (!isPortraitPWA()) return;
+  const body = document.querySelector('.body');
+  if (body) {
+    body.scrollTo({ top: 0, behavior: 'smooth' });
+  }
+}
+
+function setupPortraitPwaWatcher() {
+  applyPortraitPwaClass();
+  _portraitPwaMQ.addEventListener('change', () => {
+    applyPortraitPwaClass();
+    // Rotating into portrait-standalone: close any open sidebar drawer so the
+    // full-width layout isn't obscured.
+    if (isPortraitPWA()) closeSidebar();
+  });
+}
+
 // ============================================================================
 // Events
 // ============================================================================
@@ -2623,6 +2672,7 @@ async function boot() {
   wirePlayerEvents();
   wireUI();
   wireShortcutHelp();
+  setupPortraitPwaWatcher();
   try {
     const loaded = await API.loadData();
     if (loaded && typeof loaded === 'object') {
diff --git a/frontend/styles.css b/frontend/styles.css
index 07784b0..02a1434 100755
--- a/frontend/styles.css
+++ b/frontend/styles.css
@@ -1755,3 +1755,24 @@ input[type="range"]::-webkit-slider-thumb:hover { transform: scale(1.25); }
   .ph-logo { width: 68px; height: 68px; font-size: 26px; }
   .hero-tagline { font-size: 13px; }
 }
+
+/* ============================================================================
+ * PORTRAIT PWA — JS-class mirror (.portrait-pwa on .app)
+ *
+ * The JS layer (setupPortraitPwaWatcher in app.js) adds / removes
+ * `.portrait-pwa` on `.app` whenever the media query fires, giving a CSS hook
+ * that works inside JS-conditional code paths (e.g. scroll position checks,
+ * layout reads) without re-evaluating matchMedia inline.
+ *
+ * These selectors intentionally duplicate nothing from the @media block above
+ * — they only fill gaps that require the JS class (e.g. interaction states
+ * that can't be expressed purely with CSS media queries).
+ * ========================================================================== */
+.portrait-pwa .body {
+  /* Reinforce scroll snapping so the player stays at the viewport top after
+     JS scrolls to it; helps on iOS Safari where scroll restoration can fight. */
+  scroll-snap-type: y proximity;
+}
+.portrait-pwa .player-pane {
+  scroll-snap-align: start;
+}