Yet 15 years later, I still can't specify a width and aspect ratio for an div without some unintuitive nested div hell.
div {
width: 640px;
aspect-ratio: 16 / 9;
}So basically not supported, and you have to go back to div hell.
There should be some future.js file that you can import to make all this stuff just work in older browsers.
I've been using if for months with no issues in cross-browser testing, and I haven't enabled any experimental flags.