JSFiddle - React, Tailwind, and code Playground

by Aleksey Karagodnikov

HTML

<script src="http://fonts.googleapis.com/css?family=Roboto&amp;subset=latin,cyrillic-ext"></script>
<div class="menu-holder">
    <ul class="top-level-menu">
        <li class="top-level-menu-item"><a class="top-level-menu-link" href="/about/">О компании</a>
            <ul class="nested-menu">
                <li class="nested-menu-item"><a class="nested-menu-link" href="/about/ouradv/">Наши преимущества</a>
                </li>
                <li class="nested-menu-item"><a class="nested-menu-link" href="/about/contacts/">Контакты</a>
                </li>
            </ul>
        </li>
        <li class="top-level-menu-item"><a class="top-level-menu-link" href="/clients/">Клиенты</a>
            <ul class="nested-menu">
                <li class="nested-menu-item"><a class="nested-menu-link" href="/clients/references/">Благодарности</a>
                </li>
            </ul>
        </li>
        <li class="top-level-menu-item"><a class="top-level-menu-link" href="/gotovye_issledovaniya/">Готовые исследования и опыт</a>
        </li>
        <li class="top-level-menu-item"><a class="top-level-menu-link" href="/services/">Услуги</a>
        </li>
        <li class="top-level-menu-item"><a class="top-level-menu-link" href="/order/">Заказать</a>
        </li>
    </ul>
</div>

CSS

body {
    font-family: 'Roboto', sans-serif;
}
.top-level-menu, .nested-menu {
    font-size: 0;
    line-height: 0;
    margin: 0;
    padding: 0;
}
.top-level-menu li, .nested-menu li {
    list-style-type: none;
}
.top-level-menu-item {
    height: 100%;
    padding: 0;
    position: relative;
}
.top-level-menu-item::before {
    background-color: #90c6e0;
    content:'';
    display: block;
    height: 20px;
    left: 0;
    margin-top: -10px;
    position: absolute;
    top: 50%;
    width: 1px;
}
.top-level-menu-item:first-child::before {
    display: none;
}
.top-level-menu-item:hover .top-level-menu-link, .top-level-menu-item.active .top-level-menu-link {
    background-color: #003366;
    color: #fff;
}
.top-level-menu-item, .top-level-menu-item:hover {
    display: inline-block;
    padding: 0;
}
.top-level-menu-link, .top-level-menu-item:hover .top-level-menu-link, .nested-menu-link, .nested-menu-item:hover .nested-menu-link {
    padding: 0 10px;
}
.top-level-menu-link {
    display: block;
    color: #003366;
    font-size: 14px;
    line-height: 30px;
    margin: 0 10px;
    padding: 0 10px;
}
.top-level-menu-item:first-child .top-level-menu-link {
    margin-left: 0;
}
.top-level-menu-item:last-child .top-level-menu-link {
    margin-right: 0;
}
.top-level-menu-link {
    font-weight: bold;
    text-decoration: none;
}
.top-level-menu-item:hover .nested-menu {
    display: block;
}
.top-level-menu-item:first-child .nested-menu {
    left: 0;
}
.nested-menu {
    box-shadow: 0px 30px 29px 0px rgba(0, 0, 0, 0.35);
    background-color: #d3d3d3;
    border: 1px solid #fff;
    display: none;
    left: 10px;
    position: absolute;
    top: 100%;
    white-space: nowrap;
    z-index: 4;
}
.nested-menu-link {
    color: #003366;
    display: block;
    font-size: 14px;
    line-height: 30px;
    text-decoration: none;
}
.nested-menu-link:hover {
    text-decoration: underline;
}