I actually had the same thought and came up with a much simpler solution for this years ago, a giant box-shadow + border radius: https://codepen.io/wbobeirne/pe

I actually had the same thought and came up with a much simpler solution for this years ago, a giant box-shadow + border radius: https://codepen.io/wbobeirne/pen/WvyBQM https://codepen.io/wbobeirne/pen/WvyBQM. The mix-blend-mode trick is cool for all of the variety of effects though!