.icon-sm, .icon-md, .icon-lg, .icon-xl, .icon-xs {
  background-size: contain;
  background-position: center;
  background-repeat: no-repeat;
  display: inline-block;
}
.icon-sm {
  width:  1.5em;
  height:  1.5em;
  }
.icon-md {
  width:    2em;
  height:   2em;
}
.icon-lg {
  width:    3em;
  height:   3em;
}
.icon-xl {
  width:    4em;
  height:   4em;
}
.icon-xs {
  width: 0.75em;
  height: 0.75em;
}
