[FR]: Improving GTK theming on Helium

[KiKaraage]

Description

Apply tinted color to URL background, and maybe add outline to active tab/differentiate tab name color in GTK mode

Who's implementing?

• I'm willing to implement this feature myself

The problem

For context, I'm in Helium 0.7.2.1 on Fedora 43 + COSMIC. (iirc it's beta 9 now, the last one before GA)

I noticed some difference compared to Chrome colors:

1. The address bar tend to use default dark grey/white color for URL bar instead of omnibox_background from the theme
2. There's a prominent line below the background tabs (is it the frame color?) This makes sense in Chrome/ium, but not with Helium current layout.
3. For some reason, when I tried GTK theme in both Chrome and Helium, background of the active tab (toolbar?) has the same color as the background_tab . (Need confirmation from other users here)

GTK theme in dark mode:

GTK theme in light mode:

Comparison with default Classic color (light mode):

Comparison with one of the Chrome/Helium Colors (dark mode):

CAT mode

It's slightly better since there's no frame lines, but there's no differentiation between active tab and the others.

Possible solutions

1. Set omnibox_background to use accent color from GTK theme, like in Helium Colors mode
2. Apply similar color as background_tab for frame in GTK mode
3. Either use frame color for outline, or use it as the background for active tab (with text color inverted?) only for GTK mode. This seems harder than the other two though...

Additional context

I'm new to Chromium and I just grasp some of the assigned variables from https://github.com/Harmelodic/minimal-grey-chrome, correct me if there's anything wrong. Also want to hear feedback from other GTK theme users too!

Also thank you for bringing back support for GTK themes. Blends so well with the rest of my desktop

[dylanjames-xyz]

I am currently using Brave's GTK theme with the title bar enabled on Linux Mint 22.2, which looks fine. However, Helium's more compact layout causes elements like the tabs and search bar to overlap. Other configurations also result in a similarly busted look.

Maybe adding a small amount of whitespace might resolve the current layout issues? Regardless, I also really appreciate having support for GTK themes. Happy to look into this more if the devs don't believe it's a priority.