Where I am, to unlock a cart, you have to insert a coin, and afterwards, to get the coin back, you have to lock the cart to another cart (that's hopefully part of the pile). It mostly works.
I've tried this several times, but I'm always afraid I'll forget it's on when doing colour-sensitive work (e.g. editing photos). Your eyes adjust to the difference somewhat (so that at one point the yellow starts feeling neutral), but things would still be off in the end.
It's not a matter of just light vs dark mode, it's about the proper brightness and contrast for the ambient light you're in, i.e. having a dark theme on a 100% brightness screen in the middle of the night is not something particularly clever (and the other way around - if a light theme feels too bright, it's your display that's too bright, not necessarily the theme). If you haven't done it, research easy ways to change the hardware brightness of your screens on the go - your eyes will thank you. ClickMonitorDDC is my favourite on Windows (it works well even if it's abandonware at this point).
I personally prefer dark mode most of the time, and not like white text on black background but rather something muted with a 50-ish % gray background. I occasionally switch to light mode for when I want more contrast and I can't bring the brightness any higher (e.g. if I bring my laptop outside on a sunny day).
Depends on the implementation. If you decline, it's either 1) no cookies are written at all and you get promoted again the next time you visit that site or 2) a single cookie is written only remembering that you declined the prompt.
Do people actually sit down and watch these focused? I see longer and longer videos on YouTube because the algorithm seems to favour those, but for me, the longer it is, the more chance it has to be played as background noise or not played at all.
Vertical or horizontal?
/s