Aracari

starter-sass.scss

.drawer {
  position: absolute;
  z-index: 10;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  overflow: hidden;

  .backdrop {
    position: absolute;
    z-index: 1;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.5);
    
    &.is-open {
      opacity: 1;
    }
    
    &.is-closed {
      opacity: 0;
    }
  }

  .content {
    position: absolute;
    z-index: 2;
    left: 0;
    right: 0;
    bottom: 0;
    height: 300px;
    background: $white;
    will-change: true;

    &.is-open {
      transform: translateY(0);
    }
    
    &.is-closed {
      transform: translateY(300px);
    }
  }