Set dark mode to default regardless of user browser settings

templates/base.html

@@ -32,7 +32,8 @@
             const getTheme = () => {
                 const storedTheme = localStorage.getItem('theme');
                 if (storedTheme) return storedTheme;
-                return window.matchMedia('(prefers-color-scheme: light)').matches ? 'light' : 'dark';
+                // For new visitors, default to dark mode regardless of their OS setting.
+                return 'dark';
             };
 
             const setTheme = (theme) => {