fix unnoticeable background color bug in dark mode

components/Footer/Footer.module.css

@@ -2,7 +2,9 @@
   width: 100%;
   padding: 1.25em 1.5em;
   border-top: 1px solid var(--kinda-light);
+  background-color: var(--background-outer);
   color: var(--medium-dark);
+
   /* light-dark theme switch fading */
   transition: color 0.25s ease, background 0.25s ease, border 0.25s ease;
 }

components/Footer/Footer.tsx

@@ -3,11 +3,14 @@ import Link from "next/link";
 import classNames from "classnames";
 import { HeartIcon, NextjsLogo } from "../Icons";
 import * as config from "../../lib/config";
+import type { HTMLAttributes } from "react";
 
 import styles from "./Footer.module.css";
 
-const Footer = () => (
-  <footer className={styles.footer}>
+type Props = HTMLAttributes<HTMLDivElement>;
+
+const Footer = ({ className, ...rest }: Props) => (
+  <footer className={classNames(styles.footer, className)} {...rest}>
     <div className={styles.row}>
       <div className={styles.license}>
         Content{" "}