V2: Added Webserver for faster formatting

web/theme.js

@@ -0,0 +1,15 @@
+(() => {
+  const allowedThemes = new Set(["system", "light", "dark"]);
+  let theme = "system";
+
+  try {
+    const savedTheme = window.localStorage.getItem("roster-theme");
+    if (allowedThemes.has(savedTheme)) {
+      theme = savedTheme;
+    }
+  } catch {
+    // Storage can be unavailable in hardened or private browsing contexts.
+  }
+
+  document.documentElement.dataset.theme = theme;
+})();