.fade {
opacity: 0; transition: opacity .15s linear; &.in { opacity: 1; }
}
.collapse {
display: none; &.in { display: block; } // tr&.in { display: table-row; } // tbody&.in { display: table-row-group; }
}
.collapsing {
position: relative; height: 0; overflow: hidden; transition-timing-function: ease; transition-duration: .35s; transition-property: height;
}