I was under the impression that this has been a thing for a long while, but I checked and it's actually been available in mainstream browser versions only since

I was under the impression that this has been a thing for a long while, but I checked and it's actually been available in mainstream browser versions only since January 2021 (September for Safari, and just nine days ago for Chrome on Android). Combined global usage for supported platforms is around 84%. https://caniuse.com/mdn-css_properties_aspect-ratio https://caniuse.com/mdn-css_properties_aspect-ratio