IE8-compatible font style mixin that uses rem unit.

_font.scss

$root-font-size: 16px;
@mixin font($size, $line-height, $weight: null) {
  font-size: $size; // IE fix
  font-size: ($size / $root-font-size) * 1rem;
  @if $weight != null {
    font-weight: $weight;
  }
  line-height: $line-height;
}

// Usage example:
// p {
//  @include font(24px, 1.25, bold);
//}