there seems to be a bug where it's possible to accidentally overlay the screen yellow. i dont remember what i did to cause it unfortunately
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you highlighted the screen, the same way one can highlight text in a web page by clicking and dragging over it. I did the same thing I do that a lot, try clicking outside the game screen and it should fix that ^^ (I do that a lot tbh) You can also use the download the desktop version
idk if they can stop that from happening since its an issue with notation, bot coding, but I'd also love to see it fixxed