Custom Stylesheet: Spaced and Colored Tab Groups

[FabulousCupcake]

Some backstory:

I've been using TreeStyleTabs for a while.
It helps a lot already with organizing the tabs, but I still find it difficult to find that one tab I had open just a moment ago in the sea of tabs. I noticed that I usually still have a lot of vertical space budget that I can use; it would be awesome if I could split the 1600px tall area into 3 or 4 equally sized sections, but unfortunately I couldn't find any existing extensions on top of TST that can do this (and it doesn't seem easy to write one).

After spending some time on this, this is the alternative I came up with.
It improves the tab spatiality by adding spacing and colors to tab groups.

I think it actually ended up being pretty nice, and I'd like to share it:

Preview

 

Notes:

• I used macos + photon base theme, not sure how it will work with the other base themes (or in other OS)
• The colors are based on last digit of the parent internal tab id, so there could be adjacent tab groups with the same color

You can find it in the following github gist — just copy and paste it to the custom stylesheet section to use it:
https://gist.github.com/FabulousCupcake/9e74a35f4ef282cf90e37e11b260f6f5