FixIt/assets/css/_page/_single/_toc.scss

// Common styles for all TOC types
.toc {
  .toc-title {
    font-size: fixit-var(toc-title-font-size);
    font-weight: bold;
    text-transform: uppercase;
  }

  .toc-content {
    font-size: fixit-var(toc-content-font-size);

    code {
      @extend %code;
    }

    ul {
      margin: 0;
      text-indent: -0.8em;
      padding-left: 0.8em;
      list-style: none;

      a:first-child::before {
        content: '|';
        font-weight: bolder;
        margin-right: 0.5em;
        position: relative;
        bottom: 2px;
        color: fixit-var(single-link-color);
      }

      ul {
        padding-left: 1em;
      }
    }

    ol {
      margin: 0;
      padding-left: 2.25em;

      ol {
        padding-left: 1.25em;
      }

      li:has(> a:hover)::marker {
        color: fixit-var(single-link-color);
      }
    }
  }

  ruby {
    background-color: fixit-var(code-block-background-color);

    rt {
      color: fixit-var(secondary);
    }
  }
}

// Common active state styles for auto and dialog TOC
#toc-auto,
#toc-dialog {
  .toc-content {
    li.has-active {
      &::marker {
        color: fixit-var(single-link-color);
      }

      &:has(> .active)::marker {
        font-weight: bold;
      }

      > a {
        color: fixit-var(single-link-color);
      }
    }

    ul {
      a.active::before {
        color: fixit-var(single-link-hover-color);
      }
    }

    a.active {
      font-weight: bold;
    }
  }
}

#toc-auto {
  display: block;
  position: sticky;
  top: calc(#{fixit-var(header-height)} + #{fixit-var(breadcrumb-height)});
  box-sizing: border-box;
  visibility: hidden;
  @include overflow-wrap(break-word);
  @include blur;
  @extend .print-d-none;

  [data-header-desktop='normal'] & {
    @include set-fixit-var(scroll-mt, fixit-var(global-scroll-margin-top));
  }

  .toc-title {
    margin-block: 0 0.5em;
    cursor: pointer;
    @include user-select(none);

    &::before {
      content: '|';
      font-weight: bolder;
      margin-right: 0.5em;
      position: relative;
      bottom: 2px;
      color: fixit-var(global-border-color);
    }

    i.toc-icon {
      transition: transform 0.2s ease;
    }
  }

  &.toc-hidden i.toc-icon {
    transform: rotate(-90deg);
    transition: transform 0.2s ease;
  }

  .toc-content {
    overflow-y: scroll;
    // TODO 这里计算错误，待重构使用 JS 计算
    max-height: calc(100vh - #{2 * #{fixit-var(header-height)}});
    @include scrollbar-width(none, 0);

    &.always-active ul,
    &.always-active ol {
      display: block;
    }

    // for unordered list automatically collapsed
    ul {
      ul {
        display: none;
      }

      .has-active > ul {
        display: block;
      }
    }

    // for ordered list automatically collapsed
    ol {
      ol {
        display: none;
      }

      .has-active > ol {
        display: block;
      }
    }
  }
}

#toc-static {
  display: none;
  margin: 0.8em 0;

  &[data-kept='true'] {
    display: block;
  }

  .toc-title {
    display: flex;
    justify-content: space-between;
    line-height: 2em;
    padding: 0 0.75em;
    background-color: fixit-var(code-header-background-color);
  }

  .toc-content {
    background-color: fixit-var(code-block-background-color);

    > nav {
      > ul {
        padding: 0.4em 1em 0.4em 1.8em;

        a:hover {
          font-weight: bold;

          &::before {
            color: fixit-var(single-link-hover-color);
          }
        }
      }

      > ol {
        padding: 0.4em 1em 0.4em 2.25em;

        li:has(> a:hover)::marker,
        a:hover {
          font-weight: bold;
        }
      }
    }
  }

  &:not(.open) {
    .toc-title {
      @include set-fixit-var(code-header-background-color, darken($code-background-color, 6%));

      [data-theme=dark] & {
        @include set-fixit-var(code-header-background-color, darken($code-background-color-dark, 6%));
      }
    }
  }
}

#toc-dialog {
  transition:
    display 0.2s allow-discrete,
    overlay 0.2s allow-discrete,
    translate 0.2s,
    opacity 0.2s 0.4s;
  opacity: 0;
  translate: 100vw 0;
  width: MIN(calc(100% - 4rem), 460px);
  height: 100dvh;
  max-width: 100%;
  max-height: 100%;
  margin-right: 0;
  border: none;
  border-left: 1px solid fixit-var(global-border-color);
  background-color: fixit-var(global-background-color);

  .toc {
    max-width: 100%;
    margin-inline: 1rem;

    .toc-title {
      font-size: calc(#{fixit-var(toc-title-font-size)} * 1.5);
      line-height: calc(#{fixit-var(toc-title-font-size)} * 2);
      margin-block: fixit-var(toc-title-font-size);
    }

    .toc-content {
      font-size: MAX(fixit-var(toc-content-font-size), 1rem);

      nav {
        max-height: calc(100dvh - 5rem);
        overflow: auto;
      }
    }
  }

  &::backdrop {
    background-color: rgba(0, 0, 0, 0.25);
    backdrop-filter: blur(2px);
    transition:
      display 0.5s allow-discrete,
      overlay 0.5s allow-discrete,
      opacity 0.2s 0.4s;
    opacity: 0;
  }

  &[open],
  &[open]::backdrop {
    opacity: 1;
    transition:
      display 0.2s allow-discrete,
      overlay 0.2s allow-discrete,
      translate 0.2s,
      opacity 0.2s;
  }

  &[open] {
    translate: 0 0;
  }

  @starting-style {
    &[open],
    &[open]::backdrop {
      opacity: 0;
    }

    &[open] {
      translate: 100vw 0;
    }
  }
}

html:has(#toc-dialog[open]) {
  overflow: hidden;
}