discourse/app/assets/stylesheets/common/base/sidebar-section.scss

.sidebar-section-wrapper {
  .discourse-no-touch & {
    &:hover {
      .sidebar-section-header-wrapper {
        .btn.dropdown-select-box-header,
        .sidebar-section-header-button {
          opacity: 1;
        }
      }
    }
  }

  .sidebar-section-header-wrapper {
    display: flex;

    .discourse-no-touch & {
      &:hover {
        background: var(--d-sidebar-highlight-background);
        .d-icon-globe {
          color: var(--d-sidebar-highlight-color);
        }
      }
    }

    &:focus-within {
      background: var(--d-sidebar-highlight-background);
    }

    .sidebar-section-header-button {
      font-size: var(--font-down-1);
    }

    .btn.dropdown-select-box-header,
    .sidebar-section-header-button {
      .discourse-no-touch & {
        transition: all 0.25s;
        opacity: 0;

        &:focus {
          opacity: 1;
        }
      }

      background: transparent;
      border: none;
      margin-right: calc(var(--d-sidebar-row-horizontal-padding) / 3 * -1);
      padding: calc(var(--d-sidebar-row-horizontal-padding) / 5)
        calc(var(--d-sidebar-row-horizontal-padding) / 3);

      .d-icon {
        font-size: var(--font-down-1);
        color: var(--d-sidebar-header-icon-color);
        margin: 0;
      }

      &:focus {
        outline: none;
        background: var(--d-sidebar-highlight-hover-background);
        .d-icon {
          color: var(--d-sidebar-highlight-hover-icon);
        }
      }

      .discourse-no-touch & {
        &:hover {
          background: var(--d-sidebar-highlight-hover-background);
          .d-icon {
            color: var(--d-sidebar-highlight-hover-icon);
          }
        }
      }
    }
  }

  .sidebar-section-header {
    flex: 1 1 auto;
    color: var(--d-sidebar-header-color);
    align-items: center;
    min-width: 0;
    padding: 0;

    &.sidebar-section-header-collapsable {
      justify-content: flex-start;

      &:focus {
        background: transparent;
      }
    }
  }

  .sidebar-section-header-text {
    line-height: normal;
    margin-right: 0.25em;
    @include ellipsis;
  }

  .sidebar-section-header-global-indicator {
    margin: 0 0.75em 0 0.25em;
    font-size: var(--font-down-2);
    .d-icon {
      margin-top: -0.125em; // optical alignment
    }
  }

  .sidebar-section-header-caret {
    display: flex;
    flex: 0 0 auto;
    width: var(--d-sidebar-section-link-prefix-width);
    height: var(--d-sidebar-section-link-prefix-width);
    margin-right: var(--d-sidebar-section-link-prefix-margin-right);
    align-items: center;
    justify-content: center;

    svg {
      font-size: var(--font-down-1);
      color: var(--d-sidebar-header-icon-color);
    }
  }

  .select-kit-collection {
    .texts {
      font-size: var(--font-0);
      text-transform: none;
      line-height: var(--line-height-medium);
      .name {
        font-size: var(--font-0);
      }
    }
  }

  .sidebar-section-message-wrapper {
    display: flex;
    padding-top: 0;
    height: initial;
  }

  .sidebar-section-message {
    color: var(--primary);
    padding-left: calc(
      var(--d-sidebar-section-link-prefix-width) +
        var(--d-sidebar-section-link-prefix-margin-right)
    );
  }

  .sidebar-section-content {
    padding-bottom: 0.875em;
    margin: 0;
    hr {
      margin: 0em 1.5em;
    }
  }
}