.mui-overlay {
  position: fixed;
  height: 100%;
  width: 100%;
  z-index: 9;
  top: 0px;

  left: -100%;
  background-color: rgba(0, 0, 0, 0);
  .lh-transition(left 0ms @ease-out-function 400ms, background-color 400ms @ease-out-function 0ms);

  &.mui-is-shown {
    left: 0px;
    background-color: @light-black;
    .lh-transition(left 0ms @ease-out-function 0ms, background-color 400ms @ease-out-function 0ms);
  }
}