I think this response is more than a little unhelpful
I wanted
>> Theme support so apps can switch between light and dark themes at runtime.
You present
> IDE supports themes.
You don't see the difference?
I want to produce apps that decides, at runtime, which theme to use.
I also don't know if I'd consider it a Lazarus option if
a) It's a different language, not Delphi
and
b) It has no RAD tools.
After all, if I want niche languages with poor support for RAD, I'm spoilt for choice. What I want is for Lazarus to be updated with some modern features, not replace a well-known RAD tool with a niche, expensive, proprietary and little-known language.
You're right, I missed that you wanted styles in your app not IDE. I was thinking IDE especially re the designer, so sorry for missing that.
It's not intended to be unhelpful, and I hope the rest of what I wrote, which you didn't quote, and which I _think_ from what you wrote is of interest to you, is ok.