a.scss

@mixin collapse-sidebar {
  float: none;
  width: auto;
  clear: left;
  margin: 0;
  padding: 0 $pad-medium 1px;
  background-color: lighten($sidebar-bg, 2);
  border-top: 1px solid lighten($sidebar-border, 4);
  section {
    &.odd, &.even { float: left; width: 48%; }
    &.odd { margin-left: 0; }
    &.even { margin-left: 4%; }
  }
  &.thirds section {
    width: 30%;
    margin-left: 5%;
    &.first {
      margin-left: 0;
      clear: both;
    }
  }
}