// // Collapse // ————————————————–

.collapse {

display: none;

&.in      { display: block; }

}

.collapsing {

position: relative;
height: 0;
overflow: hidden;
transition-property: height, visibility;
transition-duration: .35s;
transition-timing-function: ease;

}

.collapse-open {

margin-top: building-units(-4);
margin-left: building-units(1);
display: block;
opacity: 0;
@include transition(opacity $transition-time-out $transition-function);

&.collapsed {
  opacity: 1;
}

}