.dropdown {
  width: 25px; }

.slide-inner {
  position: relative; }

.border_effect {
  width: 0;
  height: 0;
  position: absolute;
  top: 0;
  left: 0;
  border-style: solid;
  border-color: #CCC;
  transition: .3s;
  -webkit-transition: .3s; }

.border_effect.TL {
  border-width: 1px 0 0 1px; }

.border_effect.BR {
  border-width: 0 1px 1px 0; }