I am trying to create something similiar to the Kindle Download page: https://read.amazon.com/
, It has two buttons at the top: [CLOUD] [DOWNLOADED]
Each button can be in either a selected or non-selected state. There is always one selected (so they work as a radio button pair).
The color of the button indicates whether it is selected or not.
I like the way your CSS (MetroBlack) displays the button for button.k-state-focused, but my guess is you use that automatically, so if I click somewhere else it would lose that decoration.