          background: var(--color-dark)
  
  @include breakpoint(max, sm)
      .root
          flex: 100%
          width: 100%
 
</s> remove     .crumbs
 </s> add     .root
        flex: 100%
        width: 100%
        margin-top: var(--height-nav)
        display: block

    .section </s> remove @include breakpoint(max, sm)
    .section
        flex: 1 1 0
        padding: 1.25rem 0
        border-bottom: 1px solid var(--color-subtle)
        margin: 0

        &:not(:last-child)
            border-right: 1px solid var(--color-subtle)

 </s> add  </s> remove @include breakpoint(max, sm)
    .root
        flex: 100%
        width: 100%
        margin-top: var(--height-nav)
        display: flex
        flex-flow: row wrap
        width: 100%
 </s> add .dropdown-select
    width: 100%
    padding-left: 1rem </s> remove @include breakpoint(min, md)
    .root
        @include scroll-shadow(var(--color-back), var(--color-shadow), var(--height-nav))
        position: fixed
        top: 0
        left: 0
        width: var(--width-sidebar)
        height: calc(100vh - 3px)
        flex: 0 0 var(--width-sidebar)
        padding-top: calc(var(--height-nav) + 1.5rem)
        z-index: 10
        padding-bottom: 5rem
 </s> add .dropdown
    padding: 1rem 0
    border-bottom: 1px solid var(--color-subtle)
    width: 100%
@include breakpoint(min, md)
    .root
        @include scroll-shadow(var(--color-back), var(--color-shadow), var(--height-nav))
        position: fixed
        top: 0
        left: 0
        width: var(--width-sidebar)
        height: calc(100vh - 3px)
        flex: 0 0 var(--width-sidebar)
        padding-top: calc(var(--height-nav) + 1.5rem)
        z-index: 10
        padding-bottom: 5rem

    .dropdown
        display: none

          background: var(--color-dark)
  
@include breakpoint(min, md)
    .root
        @include scroll-shadow(var(--color-back), var(--color-shadow), var(--height-nav))
        position: fixed
        top: 0
        left: 0
        width: var(--width-sidebar)
        height: calc(100vh - 3px)
        flex: 0 0 var(--width-sidebar)
        padding-top: calc(var(--height-nav) + 1.5rem)
        z-index: 10
        padding-bottom: 5rem

    .dropdown
        display: none

  @include breakpoint(max, sm)
      .root
          flex: 100%
          width: 100%
keep add keep keep keep keep
 Use dropdown for collapsed sidebar menu 
website/src/styles/sidebar.module.sass