style: fix text selection color in Firefox dark mode

src/app/globals.css

@@ -50,7 +50,8 @@
      */
 	}
 
-   [data-theme='dark'], .dark {
+	[data-theme="dark"],
+	.dark {
 		--background: 5 5 5;
 		--foreground: 0 0% 98%;
 
@@ -95,3 +96,13 @@
 		@apply bg-background text-foreground;
 	}
 }
+
+::selection {
+	color: hsl(var(--primary-foreground));
+	background: hsl(var(--primary));
+}
+
+::-moz-selection {
+	color: hsl(var(--primary-foreground));
+	background: hsl(var(--primary));
+}