This site is a collection of useful tools, tiny tricks worth to try etc.
This particular page demonstrates a new element property - popover. Just click on the hamburger menu icon. Pure HTML + CSS with no single Javascript line. It is a long awaited feature, unfortunately missed in Firefox.
Another finding on this page are the rainbow menu items. See how it is done:
nav a {
background: linear-gradient(45deg in oklch, var(--col-2), var(--col-1));
-webkit-text-fill-color: transparent;
-webkit-background-clip: text;
background-clip: text;
}