Menu Filling Up Effect

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Menu with FillUp Hover Effect</title>
    <link rel="preconnect" href="https://fonts.googleapis.com">
    <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
    <link href="https://fonts.googleapis.com/css2?family=Poppins&display=swap" rel="stylesheet"> 
    <style>
        * {
            margin: 0;
            padding: 0;
            font-family: 'Poppins', sans-serif;
        }
        
        body {
            background-color: #292929;
        }

        section {
            display: flex;
            justify-content: center;
            align-items: center;
            width: 100%;
            height: 100vh;
        }

        ul {
            display: flex;
            list-style: none;
            gap: 15px;
        }

        ul li a {
            text-decoration: none;
            color: #fff;
            font-size: 30px;
            position: relative;
            transition: 0.8s all linear;
            padding: 5px 15px;
        }
        
        ul li a:hover {
            color: #292929;
        }

        ul li a::before {
            position: absolute;
            content: '';
            bottom: 0;
            left: 50%;
            width: 0;
            height: 0;
            background-color: #ff0;
            z-index: -1;
        }

        ul li a:hover::before {
            animation: ani 1s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
        }

        @keyframes ani {
            0% {
                width: 0%;
                height: 1px;
                left: 50%;
            }

            50% {
                width: 100%;
                height: 1px;
                left: 0;
            }

            100% {
                width: 100%;
                height: 100%;
                left: 0;
            }
        }
        
    </style>
</head>
<body>
    <section>
        <nav>
            <ul>
                <li><a class="active" href="">Home</a></li>
                <li><a href="">About Us</a></li>
                <li><a href="">Services</a></li>
                <li><a href="">Contact Us</a></li>
            </ul>
        </nav>
    </section>
</body>
</html>
                                Copy Code
                            

Result Screenshot(s)

Menu Filling Up EffectWorking Sample0