Merge pull request #80 from quoije/2026

Fix theme flash on player navigation

README.md

@@ -5,7 +5,7 @@ Little nodejs + mongodb app that I hack together with ChatGPT and Cursor to keep
 
 **Disclaimer:** This was a fun, experimental project built with “AI slop” (Cursor), so it may have security issues. For example, `python_video_server` uses the default token‑in‑URL approach to serve video files, which can leave user tokens in logs or browser history. There are ways to improve this, but at this point I’m blinder than Ray Charles.
 
-![Oscars Pool 2026](img/preview.gif)
+![Oscars Pool 2026](img/preview.png)
 
 ## Features
 

public/js/app_theme.js

@@ -1,6 +1,7 @@
 // Theme toggle with system preference fallback.
 (function () {
   const STORAGE_KEY = 'theme_preference';
+  const LAST_KEY = 'theme_last_applied';
   const THEME_ATTR = 'data-theme';
   const SOURCE_ATTR = 'data-theme-source';
   const mediaQuery = window.matchMedia('(prefers-color-scheme: dark)');
@@ -17,6 +18,11 @@
   function setTheme(theme, source) {
     document.documentElement.setAttribute(THEME_ATTR, theme);
     document.documentElement.setAttribute(SOURCE_ATTR, source);
+    try {
+      sessionStorage.setItem(LAST_KEY, theme);
+    } catch (_) {
+      // Ignore storage errors.
+    }
     updateToggleUi(theme, source);
   }
 
@@ -56,12 +62,16 @@
       if (!res.ok) return;
       const data = await res.json();
       const pref = normalizeTheme(data?.themePreference);
-      if (pref) {
+      const currentPref = normalizeTheme(localStorage.getItem(STORAGE_KEY));
-        localStorage.setItem(STORAGE_KEY, pref);
+      const changed = pref !== currentPref;
-      } else {
+      if (changed) {
-        localStorage.removeItem(STORAGE_KEY);
+        if (pref) {
+          localStorage.setItem(STORAGE_KEY, pref);
+        } else {
+          localStorage.removeItem(STORAGE_KEY);
+        }
+        applyStoredOrSystem();
       }
-      applyStoredOrSystem();
     } catch (_) {
       // Ignore fetch errors.
     }
@@ -69,8 +79,14 @@
 
   function applyStoredOrSystem() {
     const stored = normalizeTheme(localStorage.getItem(STORAGE_KEY));
-    const theme = stored || getSystemTheme();
+    let last = null;
-    const source = stored ? 'user' : 'system';
+    try {
+      last = normalizeTheme(sessionStorage.getItem(LAST_KEY));
+    } catch (_) {
+      last = null;
+    }
+    const theme = stored || last || getSystemTheme();
+    const source = stored ? 'user' : (last ? 'session' : 'system');
     setTheme(theme, source);
   }