Enhance contrast on Modern theme a bit more

[DeeJayLSP]

This will likely be divisive, probably rejected, but I still think it's contrast improvement we should discuss regardless.

A 5% increase in contrast, bumping the main color from #272727 to #292929 and contrast from 0.35 to 0.37.

Current	This PR

Also tweaks some elements to avoid contrast issues (see #112558 (comment)). There were some side effects, though, but I believe they were more positive than negative.

What I would really suggest would be #2d2d2d, which matches the luminance of many popular dark themes, with a contrast of 0.4, but that would distance itself too much from the original proposal and would be even more divisive.

Exaggerated variant preview (isolated as it's not part of this PR)

I made a little palette to compare colors:

For reference, from left to right:

• #272727 (Current color)
• #292929 (Proposed color)
• #2d2d2d (Exaggerated color)
• #3f3f3f (Halfway point between true black and true gray, slightly brighter than Godot's Gray theme)
• #7f7f7f (True gray)

[passivestar]

It needs tweaks to individual elements at this point as I hinted in my comment because while some elements gained visibility as a result of 2 global contrast bumps after the theme was ported from gdscript, some elements lost it.

For example pressed buttons need less luminance now because their icons are starting to get lost in the background:

I think it will be better to do fine color adjustments closer to release in one sweep after most of the issues are addressed and the theme is more stable, as the colors of some elements aren't final yet, i.e popup menus may need to change significantly after they get their shadows, nested tabs still need work, inspector sections need work, etc.

When we do those final color tweaks I also want to look into making text a bit brighter and repeating icons less distracting.

[DeeJayLSP]

Pushed an adjustment to button contrasts. Should solve even the first bump's contrast issue. Looking at the side effects, I believe them to be more positive than negative.

Screenshots updated.

[DeeJayLSP]

Decided to adjust the text/icon contrast too. Screenshots updated

@passivestar would you take another look?

[Calinou]

Tested locally, it works as expected. Code looks good to me.

The increased contrast helps with readability, especially in bright/outdoor environments (although a light theme is still preferable in those situations).

I've only tested this on an OLED monitor with moderate ambient lighting, so I suggest also looking at this in various conditions (e.g. no ambient lighting, some LCD monitor with poor contrast ratio, etc). This will impact how you perceive contrast.

Before	After

[passivestar]

@passivestar would you take another look?

The overall contrast change is good. Some feedback:

1. Font became too contrasty, 0.75 looks better imo.
2. You dropped button hover luminance which makes its border much more visible on hover than in its regular state, maybe button hover should be a bit brighter still
3. If we're doing all contrast tweaks in this PR could you make the hover indication in PopupMenu much more subtle? It's currently more contrasty than all other hovers in the editor
4. Tree header cells are also too dark at the moment against some backgrounds, could be made a bit brighter. Unfortunately we can't make them semi-transparent to work on different backgrounds because tree content goes under them
5. Another thing I noticed is that text in Checkboxes looks pure white (i.e look at Debugger -> Visual Profiler -> Fit To Frame), it's probably missing a color assignment or smth
6. Since you made the pressed buttons more subtle maybe this PR should close Filter sort button seems to draw more attention than needed (Modern theme) #112385

This is an improvement but as I mentioned in my previous message it's unlikely that all of these values will be final because further balancing tweaks will be needed closer to release. Later it will also probably make sense to bring the editor setting contrast back to its original 0.3 value while keeping all visual changes by doing them in theme code, just to have a less arbitrary value in settings

[DeeJayLSP]

Updated once more. This time I included button hover color and made the tweak slightly smaller.

At this point I'm just trying to slightly improve the current overall feel. Not a good idea to do many changes at once unless they break without each other.