/// Makes an element's :before pseudoelement a FontAwesome icon.
/// @param {string} $content Optional content value to use.
@mixin icon($content: false) {

  text-decoration: none;

  &:before {

    @if $content {
      content: $content;
    }

    -moz-osx-font-smoothing: grayscale;
    -webkit-font-smoothing: antialiased;
    font-family: FontAwesome;
    font-style: normal;
    font-weight: normal;
    text-transform: none !important;

  }

}

/// Applies padding to an element, taking the current element-margin value into account.
/// @param {mixed} $tb Top/bottom padding.
/// @param {mixed} $lr Left/right padding.
/// @param {list} $pad Optional extra padding (in the following order top, right, bottom, left)
@mixin padding($tb, $lr, $pad: (0,0,0,0)) {
  padding: ($tb + nth($pad,1)) ($lr + nth($pad,2)) max(0.1em, $tb - _size(element-margin) + nth($pad,3)) ($lr + nth($pad,4));
}

/// Disable's the ability for the user to select an element.
@mixin noSelect() {
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  user-select: none;
}