Any Suggestion About Browser Compatibility?

Dear All

I need some help about cross browser compatibility for my website -> https://angora.me/blog/

And here is my CSS code ->
https://angora.me/style.css

On modern browser, my website looks fine like this ->


But on some old browser, my website looks ugly like this ->


Even failed connection like this ->


I use Hugo with Netlify and Let's Encrypt SSL. I don't know if this compatibility issue is from my code side, SSL side, server side, browser side, etc? Any idea how to fix this issue?

Regards

Ignore old browsers. Some of them even don't support your SSL.

Don't bother, virtually no one is using them anymore. It's time and resources wasted. Focus on the majority of your traffic.