Works very well but on some sites the color is slightly off.

Unfortunate oversight of the addon being that the bookmark overflow menu is not affected by the colour shift which makes the appearence of the browser ui inconsistent, which can be jarring. Would love to see this issue fixed.

Its the BEST appearance extension ever. Most themes for Firefox are tolerable, not beautiful. This ext provide one of the best colors and borders scheme like mine - Borderless. Its feels really good with different color for each site, the most beautiful Ive seen from themes.
Thank for improving user experience as much as possible (for me ig)

Good extension. Would be cool if Mozilla built this in Firefox

I have no idea how this isn't built into Firefox yet.