Please implement the CSS Values specification's Toggle notation as defined in CSS Values 4 (working draft) https://drafts.csswg.org/css-values-4/#toggle-notation. The following summary and example come form that document: The toggle() expression allows descendant elements to cycle over a list of values instead of inheriting the same value. The following example makes <em> elements italic in general, but makes them normal if they’re inside something that’s italic: > em { font-style: toggle(italic, normal); } --- Issues in other browser vendor bug trackers https://bugs.chromium.org/p/chromium/issues/detail?id=715070 https://bugzilla.mozilla.org/show_bug.cgi?id=363250
This doesn't appear to be on track to be implemented by any other browsers at present.