#sidebar
  position: fixed
  top: 0
  left: -300px
  z-index: 10
  overflow-y: auto
  padding: 1rem 0 2rem .5rem
  width: $sidebar-width
  height: 100%
  background: $sidebar-background
  box-shadow: -.25rem 0 .25rem rgba(232, 237, 250, .6) inset
  opacity: .9
  transition: ease-in-out .4s

  .sidebar-toc
    ol,
    li
      list-style: none

    ol
      margin-top: .2rem
      padding-left: .4rem

    &__title
      padding-right: .5rem
      text-align: center
      font-size: unit(.9 * $rem, 'px')

    .toc-link
      display: block
      padding-left: .2rem
      border-right: 3px solid transparent
      text-decoration: none
      transition: all .2s ease-in-out

      &.active
        border-right-color: darken($cyan, 20%)
        background: $cyan
        color: $white

    &__progress
      position: relative
      margin-top: -.3rem
      padding-left: .6rem
      color: $cyan

      .progress-notice
        margin-right: .4rem

      .progress-num
        display: inline-block
        min-width: .9rem

      &-bar
        width: 0
        height: 1px
        background: $cyan