Another button hack. Button default color is blue, when button is activated, then green is added.
Again I've used smd 0605 sized rgb leds.
Yesss, they're really small. Just attach four cables ;)
Sure, the ilumination is stronger on one side. However...
Red wire is common anode which will be connected to VSS. The other yellow wires are GND for cathode with the specific color.
Connect the default color directly to GND. To add a color on activation wire to singal. When button is pressed, then connection for both led is given to GND.