hugo-theme-next/assets/css/_common/outline/sidebar/sidebar-toc.scss

.post-toc {
  font-size: $font-size-small;
  padding: 0 8px;

  .active-current {
    color: $orange;
  }

  ul {

    list-style: none;
    margin: 0;
    padding: 0 2px 5px 10px;
    text-align: left;
    counter-reset: item;

    >li {


      > ul {
        border-left: 1px solid;
        margin-left: 4px;

        li {
          position: relative;
          padding-left: 0;
          
          &:before {
            position: absolute;
            content: ' ';
            top: 0.14em;
            left: -0.75em;
            width: 0.65em;
            height: 0.815em;
            border-style: none none dashed none;
            border-width: 0.05em;
          }          
        }
      }


    }



    a {
      transition: all $transition-ease;
      border: none;
      @if $toc_number {
        &:before {
          content: counters(item, ".") ". ";
          counter-increment: item;
        }
      }

      &:hover {
        text-decoration: underline;
        color: $orange;
      }
    }
  }

  .nav-item {
    line-height: 1.8;
    overflow: hidden;
    text-overflow: ellipsis;

    @if not $toc_wrap {
      white-space: nowrap;
    }
  }

  .nav {
    .nav-child {
      display: if($toc_expand_all, block, none);
    }

    .active>.nav-child {
      display: block;
    }

    .active-current>.nav-child {
      display: block;

      >.nav-item {
        display: block;
      }
    }

    .active>a {
      border-bottom-color: $sidebar-highlight;
      color: $sidebar-highlight;
    }

    .active-current>a {
      color: $sidebar-highlight;

      &:hover {
        color: $sidebar-highlight;
      }
    }
  }
}