fcitx5: improve selection highlight readability

[yao-yun]

Description

In current fcitx5 module, the selection highlight colors are

• text: base06
• background: base04

In plenty tinted base16 schemes, base00 ~ base08 are gradient colors, and the contrast of base06 & base04 can be so low that it causes readability issue. For example, primer-dark:

I can confirm that ayu-dark is also problematic.

---

This does not align with the stylix style guide, which recommends:

• text: Default text: base05 / Alternate text: base04
• background: Selection background: base02

---

Or if the goal was to follow mallow's style, as this module is based on it, the selection text might need to be dimmed, instead of lightened. For example,

• text: base02
• background: base04

Submission Checklist

• I assert that this issue is relevant to Stylix
• I assert that this is not a duplicate of an existing issue

Notify maintainers

@make-42

[trueNAHO]

Thanks for the detailed comparison. @make-42, what should be the "correct" color in this case?

Resolving scheme inconsistencies is already on the roadmap, with the semantic representation attempting to resolve inconsistencies by design, although this will take a while to be properly resolved:

• (4) Extend and standardize color scheme
  • specs: rigorously extend the Style Guide #249
  • stylix: add Base24 support #252
  • treewide: replace custom color scheme generator with Matugen #892

-- #534

[make-42]

It depends on the base16 palette, since it looked okay with everything I tested with. Although from what I can tell, your suggestion to go from (bg/fg) 04/06 to 02/05 looks like it'd be more consistent with Stylix's guidelines indeed.

[make-42]

(and also looks better in your specific palette)

[make-42]

and also with my current palette.

[make-42]

I must've had a palette where that wasn't much of an issue when I adapted the theme back then

[make-42]

although keeping 06 for the text color might a good idea because using alternate text might decrease the contrast.

[make-42]

i'd suggest going from bg: 04 -> 02

[make-42]

Light mode (schemeless testbed):

Dark mode (dark testbed):