Update libadwaita color values for GNOME 48

[yioannides]

Closes #18 ~

I edited the light/dark theme values in src based on a recent CSS update commit I did for thunderbird-gnome-theme, but please feel free to edit this PR as you see fit.

[yioannides]

Oh it seems there are some extra values in src/themes.scss I need to modify as well, I will hopefully get to it soon

[birneee]

@yioannides thanks a lot for your efforts on this

maybe it would be better to fetch the file directly from here https://gitlab.gnome.org/GNOME/libadwaita/-/blob/main/src/stylesheet/_colors.scss

[yioannides]

How about now? I should disclaim I had to use an AI assistant this time around to go through all the values, as they were too many to go through manually like I did before, so I would appreciate it if you could confirm these work!

[birneee]

Processing all the colors by hand is a lot of effort.
I think it would be best to just fetch and use the _colors.scss directly.
And add a short script that adds a --adwaita- prefix to all colors.
Then updating the colors next time would be simple.
What do you think?

[yioannides]

I think that would be the best thing to do, considering _colors.scss keeps changing quite often.

[yioannides]

How about this?

#!/usr/bin/env bash

curl -s https://gitlab.gnome.org/GNOME/libadwaita/-/raw/main/src/stylesheet/_colors.scss \
  | sed -E 's/--([a-zA-Z0-9_-]+)/--adwaita-\1/g' \
  > adwaita_colors_test.scss

It basically changes all the-- prefixes into --adwaita-, as we discussed. If that works for our case scenario, I will leave it to you to do all the inner rewiring if that's okay, cause I am not that well versed in CSS.

[yioannides]

@birneee Do you want me to PR a shell script for the commands above and you can do the rest? (not sure how to do the CSS part)