<ul>
        <li><a href="#"></a>ANASAYFA</li>
        <li><a href="#"></a>YAZILAR</li>
        <li><a href="#"></a>KATEGORİLER</li>
</ul>

        ul {
            list-style: none;
        }

        li {
            background-color: red;
            padding: 10px;
            margin: 0 10px;
            line-height: 40px;
            display: inline-block;
            color: #fff;
            font-weight: bold;
            border-radius: 5px;
            font-size: 13px;
            position: relative;
            cursor: pointer
        }

        li::before {
            content: '';
            position: absolute;
            width: 0;
            height: 2px;
            bottom: -5px;
            background-color: #000;
            left: 0;
        }

        li:hover::before {
            width: 100%;
            transition: 300ms all;
        }