I'm not sure what color scheme you'd like to go with, but as a colorblind user, the green and yellow colors that you're currently using are very similar to me.

I'm not sure what color scheme you'd like to go with, but as a colorblind user, the green and yellow colors that you're currently using are very similar to me. Perhaps you could do a colorblind mode that uses red, blue, and yellow (out of simplicity's sake) to indicate availability? It'd make your service way more useful for me :)