Feature Request: visual feedback on button click

[NeuralBlankes]

A very minor thing, and not necessarily needed, but if there is some form of .css file that could be modified to allow for the large "train" button to go gray or some other color when you click on it, it would be nice to have. Same for the other buttons, just for visual feedback that the input was accepted.

No rush of course, and if there aren't any updates planned soon, would love to know if there's a file I can modify myself for the time being.

Thanks.