core/app/assets/stylesheets/refinery/mixins/_icon_base.scss
// we use a content block in the basic icon mixin
@mixin icon-base($colour, $size, $float:none) {
@content;
&:before {
@extend .fa;
font-size: $size;
color: $colour;
text-decoration: none;
width: auto;
height: auto;
float: $float;
}
}