Complex CSS Shape

Question

I need some CSS help. It’s hard to explain, but looking at the snippet I need the black part without the red.

I used two elements, but it should be possible with one...

.q-rounder {
  background: #222;
  width: 15px;
  height: 15px;
}

.quarter-circle {
  width: 15px;
  height: 15px;
  background: red;
  border-radius: 100px 0 0 0;
  -moz-border-radius: 100px 0 0 0;
  -webkit-border-radius: 100px 0 0 0;
}

<div class="q-rounder">
  <div class="quarter-circle"></div>
</div>

(fiddle)

Answer 1

Use a radial gradient as background

.q-rounder {
  background: 
    radial-gradient(farthest-side at bottom right,transparent 94%, #222);
  width: 15px;
  height: 15px;
}

<div class="q-rounder">
</div>

Another syntax with the at to have better support (safari doesn't support the at)

.q-rounder {
  background: 
    radial-gradient(farthest-side,transparent 94%, #222) top left/200% 200%;
  width: 15px;
  height: 15px;
}

<div class="q-rounder">
</div>