Created attachment 460218 [details]
screenshot of bug
The source of this bug can be found here:
Isolated example: https://codepen.io/brandonmcconnell/pen/jOZXdzg/f089181395b1ffd8812a16e6b5c96e7b?editors=1100
When using an opacity value from a CSS variable as the alpha channel value in an `rgb()` **for a ::marker pseudo-element's color**, neither the color nor the opacity values are rendered.
*** This bug has been marked as a duplicate of bug 241566 ***
Created attachment 460223 [details]
Looks like we disallow custom property declarations on ::marker rules altogether.