Generated by SassMeister.com.

SassMeister-input.scss

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

$icons: (
    "play": "\f04b",
    "pause": "\f04c"
);

@mixin icon($font){
    &:before{
        font-family: 'FontAwesome';
        speak: none;
        font-style: normal;
        font-weight: normal;
        font-variant: normal;
        text-transform: none;
        line-height: 1;

        /* Better Font Rendering =========== */
        -webkit-font-smoothing: antialiased;
        -moz-osx-font-smoothing: grayscale;

        content: map-get($icons, $font);
    }
}

@each $icon, $code in $icons {
    .fa.fa-#{$icon}{
        @include icon(#{$icon})
    }
}

SassMeister-output.css

@charset "UTF-8";
.fa.fa-play:before {
  font-family: 'FontAwesome';
  speak: none;
  font-style: normal;
  font-weight: normal;
  font-variant: normal;
  text-transform: none;
  line-height: 1;
  /* Better Font Rendering =========== */
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  content: "";
}

.fa.fa-pause:before {
  font-family: 'FontAwesome';
  speak: none;
  font-style: normal;
  font-weight: normal;
  font-variant: normal;
  text-transform: none;
  line-height: 1;
  /* Better Font Rendering =========== */
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  content: "";
}