Check your site to see where you can replace your code with modern CSS
Paste any public URL and it opens the page in Chrome, explores its interactions, then checks the HTML, CSS, and JavaScript for things that browsers can now handle natively.
It catches patterns such as custom accordions, popovers, dialogs, scroll reveals, JavaScript sticky elements, and older CSS workarounds.
The report includes the code it found, a proposed replacement, browser support, what to verify before changing anything, and a small example towards a codepen to implement it.
It scans ONE page, so it is not a performance, accessibility, security, or full-site audit.
It is free (10 url/day/human) and requires no account.