Chrome shipped customizable select elements first, and as of Safari 27.1, October 23, Apple joined in. Writing appearance: base-select in your CSS turns the native dropdown into HTML you can actually style, while keeping native behaviour for keyboard, screen readers and everything else that reason made select hard in the first place.
The support story today
caniuse data puts customization of select at 69.98 percent of browsers: Chrome, Safari and their derivatives ship it, Firefox does not yet. That is a degrading feature, not a broken one. Firefox users get a plain, perfectly working native dropdown.
What you can do now that you couldn't
- Real colours, borders and states inside the popup list, without a dropdown library.
- An option rendering a small icon next to its label.
- The still-strong argument for native semantics: input handling, focus, voice control all stay in the browser's hands, not the library's.
Good progressive enhancement is styling what the browser has already made accessible. That is gacor.
Firefox hasn't shipped it yet, so if your design does not survive a fallback, keep appearance default until it does. A small feature, useful to roughly seven readers in ten.