Border support

[popov654]

It would be really great if I could have a customizable in color 1px stroke around tabs (not only the customizable background). Is this possible using SVG?

[pathbreak]

I tried a number of things, but I'm unable to make it work, sorry.
In theory, adding a second SVG path that is a copy of the curved portions but with a different stroke color should have displayed tabs with border. But this approach did not work for me - it disabled the entire green background, for reasons I'm unable to understand.

I suggest asking the author of https://github.com/wilfredwee/photon-australis from whom I adapted this project. Their SVG knowledge is surely far better than mine.

[popov654]

I think you could probably look at Palemoon Australis theme - it has borders on tabs and also uses SVG. Btw, did you try to use ::before and ::after for left and right arc segments?