Generated by SassMeister.com.

SassMeister-input-HTML.html

<div class="circle-thing">foo</div>

SassMeister-input.scss

// ----
// Sass (v3.4.12)
// Compass (v1.0.3)
// ----

@import "compass";

@include keyframes(expand-o-band) {
	0% {
	  /* prefixed property */
		@include border-radius(0);
	}

	100% {
		@include border-radius(1em);
		@include background(linear-gradient(to bottom, black, white));
	}
}

.circle-thing {
	@include animation(expand-o-band 1.5s infinite);
  background: yellow;
	padding: 5em;
	border: 1px solid;
}

SassMeister-output.css

@-moz-keyframes expand-o-band {
  0% {
    /* prefixed property */
    -moz-border-radius: 0;
    border-radius: 0;
  }
  100% {
    -moz-border-radius: 1em;
    border-radius: 1em;
    background: -moz-linear-gradient(top, #000000, #ffffff);
    background: linear-gradient(to bottom, #000000, #ffffff);
  }
}
@-webkit-keyframes expand-o-band {
  0% {
    /* prefixed property */
    -webkit-border-radius: 0;
    border-radius: 0;
  }
  100% {
    -webkit-border-radius: 1em;
    border-radius: 1em;
    background: -webkit-linear-gradient(top, #000000, #ffffff);
    background: linear-gradient(to bottom, #000000, #ffffff);
  }
}
@keyframes expand-o-band {
  0% {
    /* prefixed property */
    -moz-border-radius: 0;
    -webkit-border-radius: 0;
    border-radius: 0;
  }
  100% {
    -moz-border-radius: 1em;
    -webkit-border-radius: 1em;
    border-radius: 1em;
    background: -webkit-gradient(linear, 50% 0%, 50% 100%, color-stop(0%, #000000), color-stop(100%, #ffffff));
    background: -moz-linear-gradient(top, #000000, #ffffff);
    background: -webkit-linear-gradient(top, #000000, #ffffff);
    background: linear-gradient(to bottom, #000000, #ffffff);
  }
}
.circle-thing {
  -moz-animation: expand-o-band 1.5s infinite;
  -webkit-animation: expand-o-band 1.5s infinite;
  animation: expand-o-band 1.5s infinite;
  background: yellow;
  padding: 5em;
  border: 1px solid;
}

SassMeister-rendered.html

<div class="circle-thing">foo</div>