Support light theme
Being outdoors in brighter sun, it is somewhat common for me to be unable to lock the phone in any way other than 99% blindly because I can't really see anything. The PinePhone in particular just doesn't have a screen that is bright enough for these conditions (might be less of an issue with the Librem 5). Once the device is unlocked however, things tend to be mostly fine - because I use all apps on my phone with black text on white bg so they're all super bright, which somehow also makes the text just about readable under most conditions where dark mode-alikes fail. I'm not sure why exactly it is like that, but it seems like white on dark like the lock screen is just inherently way less usable under direct light.
Therefore, I'm suggesting that the settings have an easy toggle to make the lockscreen (both the clock view when not scrolled up to the PIN unlock part, and the PIN keyboard itself) a bright white with black text & elements, so the exact opposite to what it is now. I would suggest to not tie this to the notification bar color when unlocked and general app dark mode or anything else, since this is only really a usability issue for me on the lock screen anyway, and I feel like that might also be the case for others.
I don't care if it's the default, the current black certainly looks sleek and I'm sure a lot of people are fine with it. But those who find the sunlight issues a bit too much to deal with, might be worth a toggle.