I don't quite get why you are complaining about Firefox. I'm on the Aurora series, and using the default theme; the buttons are colourful when enabled, and grey

I don't quite get why you are complaining about Firefox. I'm on the Aurora series, and using the default theme; the buttons are colourful when enabled, and grey when disabled. No matter what series you're on, Firefox has a plethora of themes to pick from, including some that give it Chrome-like tabs.