app/assets/stylesheets/general/_icons.sass

Summary

Maintainability
Test Coverage
.icon-extend
  font-family: 'madek-icon-font'
  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

// match our icons as well as generic font-awesome
[class*="icon-"], [class*="fa-"]
  font-size: 16px

  &.bright
    color: $white

  &.mid
    color: $mono-mid

  &.branded
    color: $main-color

  &.small
    font-size: 12px

// Icon Font Extensions

.active > .icon-checkbox:before,
.icon-checkbox.active:before,
.icon-checkbox-active:before
  content: "\e62e"

.icon-star-empty.active:before,
.active > .icon-star-empty:before,
.icon-star:before
  content: "\e614"

// Icon Aliases
.icon-filter-set
  @extend .icon-filter

// Goodies from font awesome
.icon-fixed-width 
  width: 1.28571em
  text-align: center