Small Size

<button class="flat xs grey">Grey</button>

Grey Green Purple Navy Blue Pink Blue Yellow

Normal Size

<button class="flat sm grey">Grey</button>

Grey Green Purple Navy Blue Pink Blue Yellow

Medium Size

<button class="flat md grey">Grey</button>

Grey Green Purple Navy Blue Pink Blue Yellow

Large Size

<button class="flat lg grey">Grey</button>

Grey Green Purple Navy Blue Pink Blue Yellow