Bootstrap/site/assets/scss/_toc.scss

// stylelint-disable selector-max-type

.bd-toc {
  @include media-breakpoint-up(lg) {
    position: sticky;
    top: 5rem;
    right: 0;
    z-index: 2;
    height: subtract(100vh, 7rem);
    overflow-y: auto;
  }

  nav {
    @include font-size(.875rem);

    ul {
      padding-left: 0;
      list-style: none;

      ul {
        padding-left: 1rem;
        margin-top: .25rem;
      }
    }

    li {
      margin-bottom: .25rem;
    }

    a {
      color: inherit;

      &:not(:hover) {
        text-decoration: none;
      }

      code {
        font: inherit;
      }
    }
  }
}