.aside {
  width: 400px;

  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  background-color:#fff;


  box-shadow: 0 5px 15px rgba(0, 0, 0, 0.5);
  z-index: 2000;
  width: 0px;
  min-width: 0px;

  transition: 0.1s width ease, 0.1s min-width ease;
}

.aside.in {
 
  min-width: 400px;
}

.aside-backdrop {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  z-index: 1040;
  background-color: #000;
  transition: 0.1s opacity ease;
  opacity: 0;
  display: none;
}

.aside-backdrop.in {
  display: block;
  opacity: 0.5;
}