A CodePen by Marcello Africano.

index.html

<!-- CSSDeck Logo -->
<div id="circle">
  <div id="ring
  <div id="ring"></div>
</div>

style.scss

@import "compass";
/* Variables */
$circle-color: #000;
$circle-size: 125px;
$circle-roundness: 50%;

$ring-color: #000;

/* Inner Circle */
#circle {
  margin: 100px auto;
  background-color: $circle-color;
  width: $circle-size;
  height: $circle-size;
  border-radius: $circle-roundness;
}

#ring {
  background-color: $ring-color;
}