/*drop*/
.dropdown-menu {
    max-height: 400px;
    overflow: hidden;
    overflow-y: auto;
}

a.dropdown-toggle {
    position: relative;
}

a.dropdown-toggle::before {
    content: '';
    display: inline-block;
    border-left: 7px solid transparent;
    border-right: 7px solid transparent;
    border-bottom: 7px solid #CCC;
    border-bottom-color: rgba(0, 0, 0, 0.2);
    position: absolute;
    bottom: -2px;
    right: 18px;
    display: none;
}
a.dropdown-toggle::after {
    content: '';
    display: inline-block;
    border-left: 6px solid transparent;
    border-right: 6px solid transparent;
    border-bottom: 6px solid white;
    position: absolute;
    bottom: -2px;
    right: 18px;
    z-index: 1001;
    display: none;
}

.open > a.dropdown-toggle::before,
.open > a.dropdown-toggle::after {
    display: block;
}