Cool!
For the 'switch-background' animation, you might want to consider using steps as the timing function (instead of linear), and then the keyframes can be more readable.
Thanks! 😀 I didn't know about this option. That being said, I am still not quite happy about the easing. I set "animation-timing-function: ease-out;" at 80% but it should actually be at 75%, but somehow this doesn't work. The original animation by @justvanrossum looks better.