Use CSS media block for dark theme

Moved CSS dark theme rules into a media dark theme to automatically use
it if the user device is configured to prioritize dark themes.

src/en/assets/luca0n.css

@@ -144,39 +144,41 @@ p {
 /**************/
 /* Dark theme */
 /**************/
-body {
+@media (prefers-color-scheme: dark) {
+	body {
 		background-color: #222;
 		color: #ddd;
-}
-footer {
+	}
+	footer {
 		color: #bbb;
-}
+	}
 
-main a {
+	main a {
 		color: #1ca6c6;
 		transition: color 0.08s linear 0s;
-}
-main a:visited {
+	}
+	main a:visited {
 		color: #c658e6;
-}
-main a:hover {
+	}
+	main a:hover {
 		color: #63cae1;
-}
-header a {
+	}
+	header a {
 		color: #0d2f95;
 		transition: color 0.08s linear 0s;
-}
-header a:visited {
+	}
+	header a:visited {
 		color: #650a73;
-}
+	}
 
-.button:hover {
+	.button:hover {
 		background-color: rgb(225, 178, 117);
-}
+	}
 
-.contentWarning {
+	.contentWarning {
 		color: black;
 		background: linear-gradient(to top, rgb(238, 112, 0), rgb(255, 178, 30));
+	}
 }
 
 @media screen and (max-width: 768px) {