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

.header-sidebar-toggle {
  margin-right: 1em;
  margin-left: -10px;

  button {
    position: relative;
    font-size: var(--font-up-2);

    .discourse-no-touch & {
      &:hover {
        background: var(--primary-low);
        .d-icon {
          color: var(--primary-medium);
        }
      }
    }
  }
}

#main-outlet-wrapper {
  .sidebar-wrapper {
    grid-area: sidebar;
    position: sticky;
    top: var(--header-offset);
    height: calc(100vh - var(--header-offset));
    align-self: start;
    overflow-y: auto;
    background-color: var(--primary-very-low);
  }

  .sidebar-container {
    box-sizing: border-box;
    height: 100%;
    width: 240px;
    padding: 1em 0.5em 1em 0;
  }

  .sidebar-toggle {
    display: flex;
    justify-content: flex-end;
  }

  .sidebar-section-wrapper {
    margin-bottom: 1em;
  }

  .sidebar-section-header {
    display: flex;
    text-transform: uppercase;
    font-size: 1em;
    font-weight: bold;
    align-items: center;
  }

  .sidebar-section-header-link {
    &:visited {
      color: var(--primary);
    }

    &:hover {
      background: var(--primary-low);
    }

    flex: 1 1 auto;
    color: var(--primary);
    font-size: var(--font-down-1);
    padding: 0.25em 0.5em;
  }

  .sidebar-section-header-button {
    background: none;
    border: none;
    padding: 0.25em 0.5em;

    .d-icon {
      font-size: $font-down-1;
      color: var(--primary-medium);
    }

    &:hover {
      background: var(--primary-low);
    }
  }

  .sidebar-section-link-wrapper {
    margin-left: 1.5em;
    display: flex;
    align-items: center;
  }

  .sidebar-section-link {
    flex: 1 1 0;
    display: flex;
    padding: 0.25em 0.5em;
    color: var(--primary-high);
    font-size: var(--font-down-1);

    &:hover {
      background: var(--primary-low);
    }

    &.active {
      color: var(--primary);
      font-weight: bold;
    }

    .badge-wrapper {
      font-size: 100%;
    }
  }

  .sidebar-section-message-wrapper {
    display: flex;
    margin-left: 1.5em;
  }

  .sidebar-section-message {
    padding: 0.25em 0.5em;
    font-size: var(--font-down-1);
    color: var(--primary-high);
  }

  .sidebar-section-link-content-badge {
    color: var(--tertiary);
    font-size: var(--font-down-1);
    font-weight: normal;
    margin-left: auto;
  }

  .sidebar-section-header-caret {
    width: 1.5em;
    display: flex;
    justify-content: center;
    border: none;
    background-color: transparent;

    &:hover {
      opacity: 100;
    }

    opacity: 0;

    .d-icon {
      font-size: $font-down-1;
      color: var(--primary-medium);
    }
  }

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

  .sidebar-section-link-personal-messages-sent,
  .sidebar-section-link-personal-messages-new,
  .sidebar-section-link-personal-messages-archive,
  .sidebar-section-link-personal-messages-unread,
  .sidebar-section-link-group-messages-new,
  .sidebar-section-link-group-messages-unread,
  .sidebar-section-link-group-messages-archive {
    margin-left: 0.5em;
  }
}