adds dark mode

assets/js/darkmode.js

@@ -0,0 +1,19 @@
+// Set initial theme on page load
+(function() {
+  const isDark = localStorage.theme === "dark" ||
+    (!("theme" in localStorage) && window.matchMedia("(prefers-color-scheme: dark)").matches);
+  document.documentElement.classList.toggle("dark", isDark);
+
+  // Update label on load
+  const label = document.getElementById("darkmode-label");
+  if (label) label.textContent = !isDark ? "Dark" : "Light";
+})();
+
+// Toggle dark mode and update label/localStorage
+function toggleDarkMode() {
+  const html = document.documentElement;
+  const isDark = html.classList.toggle("dark");
+  localStorage.theme = isDark ? "dark" : "light";
+  const label = document.getElementById("darkmode-label");
+  if (label) label.textContent = !isDark ? "Dark" : "Light";
+}