I've began using dark theme on Arduino ide and I like it a lot. I find it easier to spot things in my code when using dark theme. Only problem I am have with it is the little info box that pops up on top about which function the bracket you selected corresponds too. The thing is, this little box was made for default theme and in the dark theme, the text turns out white on a tan background blending together making it very difficult to read on the screen. I use that little info box a lot as it prevents from having to jump around my code back and forth too much. I was wondering if somewhere in the theme syntax/svg/xml files there is a way to change the background color of the box to make it easier to read from.
I think the forum category you chose is correct for that Arduino IDE version.
I'm not aware of a theme setting that affects this UI element, but I might have missed it since my knowledge of the theme system is based only on a lot of trial and error experimentation.
I have the feeling that the theme system of Arduino IDE 2.x will be more full featured. I'm not aware of any tutorials for customizing its theme, but the IDE is based on the same framework as VS Code, so I believe any of the many VS Code themes can be applied with a bit of effort, and likely there is a lot of general documentation available for that theme system. But better yet, it comes with four themes pre-installed, two of which are dark themes, so it's likely that most people will be satisfied with the selection that's available out of the box.
Thank you very much for your help and effort. Every theme I tried so far does not change the color of that box. I have a feeling that it might be hidden not in the theme itself but somewhere in the source code of Arduino. I hope someone will figure it out soon, that will be awesome.