Generated by SassMeister.com.

SassMeister-input-HTML.html

<section></section>

SassMeister-input.scss

// ----
// Sass (v3.3.4)
// Compass (v1.0.0.alpha.18)
// ----

@keyframes rotation {
	to {
		-webkit-transform: rotate(1turn);
		transform: rotate(1turn);
	}
}

@-webkit-keyframes rotation {
	to {
		-webkit-transform: rotate(1turn);
		transform: rotate(1turn);
	}
}
section:hover {
	animation: rotation 1s linear infinite;
	-webkit-animation: rotation 1s linear infinite;
}

@mixin yin-yang($width) {
section {
	position: relative;
	width: $width;
	height: $width/2;
	border-color: red;
	border-style: solid;
	border-width: 2px 2px $width/2 + 2px 2px;
	border-radius: 100%;
	background: #eee;
}

section:before {
	position: absolute;
	top: 50%;
	left: 0;
	width: $width/8;
	height: $width/8;
	border: 3*$width/16 solid red;
	border-radius: 100%;
	background: #eee;
	content: "";
}

section:after {
	position: absolute;
	top: 50%;
	left: 50%;
	width: $width/8;
	height: $width/8;
	border: 3*$width/16 solid #eee;
	border-radius: 100%;
	background: red;
	content: "";
}
}
@include yin-yang(160px);

SassMeister-output.css

@keyframes rotation {
  to {
    -webkit-transform: rotate(1turn);
    transform: rotate(1turn);
  }
}
@-webkit-keyframes rotation {
  to {
    -webkit-transform: rotate(1turn);
    transform: rotate(1turn);
  }
}
section:hover {
  animation: rotation 1s linear infinite;
  -webkit-animation: rotation 1s linear infinite;
}

section {
  position: relative;
  width: 160px;
  height: 80px;
  border-color: red;
  border-style: solid;
  border-width: 2px 2px 82px 2px;
  border-radius: 100%;
  background: #eee;
}

section:before {
  position: absolute;
  top: 50%;
  left: 0;
  width: 20px;
  height: 20px;
  border: 30px solid red;
  border-radius: 100%;
  background: #eee;
  content: "";
}

section:after {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 20px;
  height: 20px;
  border: 30px solid #eeeeee;
  border-radius: 100%;
  background: red;
  content: "";
}

SassMeister-rendered.html

<section></section>