<div class='h12 bg-darken10 relative round-full'>
  <div class='absolute h12 bg-green-light round-full' style='width:50%;'></div>
</div>

<div class='flex flex--row flex--center-cross border border--gray-light round-l'>
    <button class='py18 pr12 pl18 border-r border--gray-light bg-white bg-green-light-on-hover cursor-pointer round-l'>
      <div class='triangle--r triangle color-green color-green'></div>
    </button>
    <div class='flex-child-grow px18 py18 bg-white'>
      <div class='relative w-full h12 bg-darken10 round-full'>
        <div class='absolute top right bottom left m3 bg-green-light round-full' style='width:50%;'>
          <span class='absolute top right w30 h-full bg-green round-full'></span>
        </div>
      </div>
    </div>
  </div>