.icon {
  width: 1em;
  height: 1em;
  display: inline-block;
  vertical-align: -0.125em;
  flex-shrink: 0;
}
.icon-lg { width: 1.35em; height: 1.35em; }
.icon-xl { width: 1.6em; height: 1.6em; }
.icon-sm { width: 0.85em; height: 0.85em; }