Why do buttons sometimes turn red?
It’s meant to be a lightweight way of protecting you from misclicks. If you try to do something that seems unusual (like ending your turn when you could play or buy more cards), the game will pause a second and turn the thing you clicked red. If you really want to do that, just click it again. Here I clicked +$2 when I could have played either of two actions. If playing the treasure is really what I wanted to do, I just have to click the +$2 button again to confirm it.
