IPython/html/static/notebook/less/menubar.less

#menubar {
  .border-box-sizing();

  .navbar {
    border-top: 1px;
    border-radius: 0px 0px @border-radius-base @border-radius-base;
    margin-bottom: 6px;
  }
  
  .navbar-toggle {
    float: left;
  }
  .navbar-collapse {
    clear: left;
  }
  
}

.nav-wrapper {
  border-bottom: 1px solid @navbar-default-border;
}

i.menu-icon {
  // add padding to account for float-right
  padding-top: 4px;
}

ul#help_menu li a{
    overflow: hidden;
    padding-right: 2.2em;
    i {
        margin-right: -1.2em;
    }
}

// Make sub menus work in BS3.
// Credit: http://www.bootply.com/86684
.dropdown-submenu {
    position: relative;
}

.dropdown-submenu>.dropdown-menu {
    top: 0;
    left: 100%;
    margin-top: -6px;
    margin-left: -1px;
    -webkit-border-radius: 0 6px 6px 6px;
    -moz-border-radius: 0 6px 6px 6px;
    border-radius: 0 6px 6px 6px;
}

.dropdown-submenu:hover>.dropdown-menu {
    display: block;
}

.dropdown-submenu>a:after {
    display: block;
    content: " ";
    float: right;
    width: 0;
    height: 0;
    border-color: transparent;
    border-style: solid;
    border-width: 5px 0 5px 5px;
    border-left-color: #cccccc;
    margin-top: 5px;
    margin-right: -10px;
}

.dropdown-submenu:hover>a:after{
    border-left-color: #ffffff;
}

.dropdown-submenu.pull-left {
    float: none;
}

.dropdown-submenu.pull-left>.dropdown-menu {
    left: -100%;
    margin-left: 10px;
    -webkit-border-radius: 6px 0 6px 6px;
    -moz-border-radius: 6px 0 6px 6px;
    border-radius: 6px 0 6px 6px;
}