fix(web): dark mode text color fixes

fixes #544

web/src/components/Heading.jsx

@@ -1,9 +1,5 @@
 import { h } from 'preact';
 
 export default function Heading({ children, className = '', size = '2xl' }) {
-  return (
-    <h1 className={`font-semibold tracking-widest text-gray-900 uppercase dark:text-white text-${size} ${className}`}>
-      {children}
-    </h1>
-  );
+  return <h1 className={`font-semibold tracking-widest uppercase text-${size} ${className}`}>{children}</h1>;
 }