framework/less/lib/sideNav.less

.sideNav > ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

// On phones, the index sidebar will pretty much take care of itself. The
// navigation list is a .dropdown-select and will be shown as the title-
// control; the new discussion button is the primary-control. On anything
// larger than a phone, however, we need to affix the sidebar and expand the
// .dropdown-select into a plain list.
@media @tablet-up {
  .sideNav {
    // Expand the dropdown-select component into a normal nav list.
    & .Dropdown--select {
      display: block;

      .Dropdown--expanded();

      & .Dropdown-menu {
        & > li > a {
          padding: 8px 0 8px 30px;
          color: @muted-color;

          &:hover {
            background: none;
            color: @link-color;
            text-decoration: none;
          }

          & .Button-icon {
            float: left;
            margin-left: -30px;
            margin-top: 1px;
            font-size: 15px;
          }
        }
        & > li.active > a {
          background: none;
          color: @primary-color;
          font-weight: bold;
        }
        & > .Dropdown-separator {
          background: none;
        }
      }
    }
  }
}

.sideNav--horizontal {
  padding: 15px 0;
  white-space: nowrap;
  overflow: auto;
  -webkit-overflow-scrolling: touch;

  &:after {
    content: " ";
    position: absolute;
    left: 0;
    right: 0;
    margin-top: 15px;
    border-bottom: 1px solid @control-bg;
  }

  > ul > li, .Dropdown-menu > li {
    display: inline-block;
    margin: 0 20px 0 0;
    vertical-align: top;
  }
  .Dropdown-separator {
    display: none;
  }

  .Dropdown--select .Dropdown-menu > li > a {
    padding-left: 25px;

    .icon {
      margin-left: -25px;
    }
  }

  .affix {
    position: static;
  }
}
@media @tablet {
  .sideNav {
    .sideNav--horizontal();
  }
}

@media @desktop-up {
  .sideNav {
    float: left;

    &, > ul {
      width: 175px;
    }
    > ul {
      margin-top: 30px;

      &.affix {
        top: @header-height;
      }
      > li {
        margin-bottom: 10px;
      }
    }
  }
}

@media @phone, @tablet {
  .sideNavOffset {
    margin-top: 15px;
  }
}

@media @desktop-up {
  .sideNavOffset {
    margin-top: 30px;
    margin-left: 225px;
  }
}