@mixin overlay {
  .overlay {
    bottom: 0;
    left: 0;
    position: fixed;
    right: 0;
    top: 0;
    transition: opacity 0.3s ease-in-out;

    &.is-collapsible {
      &.collapse {
        display: none;

        &.in {
          display: block;
        }
      }
    }
  }
}