How to target Safari 16+ with a CSS @supports media query

I just spent over 30 minutes looking for a way to target Safari with CSS media queries and could not find a reliable way that works with Safari 17 without also targeting Chrome.

Looking through the compatibility table on caniuse.com you can spot that Safari 16+ has a unique property which is not supported by Chrome or Firefox called hanging-punctuation.

Using that property and -webkit-appearance we can target Safari specifically until any other browser decides to support it.

1@supports (hanging-punctuation: first) and (-webkit-appearance: none) {
2  .safari-only {
3    background-color: red;
4  }
5}

Demo

If you open this page in Safari, the right column will be red.

Nice, but why does it also target Arc, Chrome, Firefox, Brave, Internet Explorer, etc. on my iPhone or iPad?

Because iOS and iPadOS use the Mobile Safari rendering engine for all webviews. This means if you are using Chrome or any other “browser” on your iPhone it is still Safari under the hood.