twbs--bootstrap/docs/assets/scss/_sidebar.scss

//
// Side navigation
//

.bd-sidebar {
  padding: 0;
  margin-bottom: 0;
  background-color: #fafafa;

  .navbar-toggler {
    position: absolute;
    top: 1rem;
    right: 0;
    z-index: 5;
  }
}

.bd-sidebar .navbar-header {
  float: none;
  margin-right: -15px;
}

.bd-sidebar .navbar-collapse {
  padding: 0;
  border: 0;
}

@media (min-width: 992px) {
  .bd-docs {
    margin-left: 240px;
  }
  .bd-sidebar {
    position: fixed;
    top: 0;
    bottom: 0;
    left: 0;
    width: 240px;
    overflow-y: auto;
    border-right: 1px solid #eee;
    -webkit-transform: translated3d(0,0,0); // Ensure proper scrolling of sidebar
  }
}

.bd-sidebar .navbar-brand {
  display: block;
  float: none;
  height: auto;
  padding: 1.55rem 1.25rem;
  font-size: 20px;
  font-weight: 500;
  line-height: 1;
  // color: #fff;
}
.bd-sidebar-brand:hover,
.bd-sidebar-brand:focus {
  // color: #fff;
  text-decoration: none;
}

.bd-search {
  position: relative;
  margin-right: 1.25rem;
  margin-bottom: 1.5rem;
  margin-left: 1.25rem;

  .form-control {
    height: 2.45rem;
    padding-top: .4rem;
    padding-bottom: .4rem;
  }
}

.bd-search-results {
  right: 0;
  display: block;
  padding: 0;
  overflow: hidden;
  font-size: .9rem;

  &:empty {
    display: none;
  }

  > li > a {
    padding-left: .75rem;
    padding-right: .75rem;
  }

  > li:first-child { margin-top: .25rem; }
  > li:last-child { margin-bottom: .25rem; }

   > .no-results {
    padding: .75rem 1rem;
    color: #7a7a7a;
    text-align: center;
  }
}


.bd-sidenav {
  display: none;
}

.bd-toc-link {
  display: block;
  padding: .25rem 1.25rem;
  color: $gray;
  // font-size: 1rem;
  // color: #fff;
}
.bd-toc-link:hover,
.bd-toc-link:focus {
  // color: $bd-yellow;
  color: $brand-primary;
  text-decoration: none;
}
.active > .bd-toc-link {
  font-weight: 500;
  color: $gray-dark;
  // color: $bd-yellow;
}
.active > .bd-sidenav {
  display: block;
}

.bd-toc-item.active {
  margin-top: 1rem;
  margin-bottom: 1rem;
}
.bd-toc-item:first-child {
  margin-top: 0;
}
.bd-toc-item:last-child {
  margin-bottom: 2rem;
}

// All levels of nav
.bd-sidebar .nav > li > a {
  display: block;
  padding: .25rem 1.25rem;
  font-size: 90%;
  color: #99979c;
}
.bd-sidebar .nav > li > a:hover,
.bd-sidebar .nav > li > a:focus {
  color: $brand-primary;
  // color: $bd-yellow;
  text-decoration: none;
  background-color: transparent;
}
.bd-sidebar .nav > .active > a,
.bd-sidebar .nav > .active:hover > a,
.bd-sidebar .nav > .active:focus > a {
  font-weight: 500;
  color: $gray-dark;
  // color: $bd-yellow;
  background-color: transparent;
}

// Nav: second level (shown on .active)
.bd-sidebar .nav .nav {
  display: none; // Hide by default, but at >768px, show it
  padding-bottom: .75rem;
}
.bd-sidebar .nav .nav > li > a {
  padding-top: 1px;
  padding-bottom: 1px;
  padding-left: 2rem;
  font-size: 75%;
  font-weight: normal;
}
.bd-sidebar .nav .nav > .active > a,
.bd-sidebar .nav .nav > .active:hover > a,
.bd-sidebar .nav .nav > .active:focus > a {
  font-weight: 500;
}

.bd-sidebar .nav > .active > .nav {
  display: block;
}
.bd-sidebar .nav .nav > li > a {
  padding-top: .125rem;
  padding-bottom: .125rem;
  padding-left: 2rem;
  font-size: 80%;
}