add dark mode

templates/main.css

@@ -131,4 +131,23 @@ main footer {
 .message {
     text-align: center;
     padding: 2em;
+}
+
+@media (prefers-color-scheme: dark) {
+    body {
+        background: #141414;
+        color: #e3e3e3;
+    }
+
+    a {
+        color: aqua;
+    }
+
+    a:visited {
+        color: mediumpurple;
+    }
+
+    nav h1 a {
+        color: white;
+    }
 }