Menubar with Moving Hover

<!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>Magic Background Menubar</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 {
            width: 100%;
            height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
        }

        nav {
            width: 550px;
            display: flex;
            gap: 1px;
            border-radius: 5px;
            background-color: #05a888;
            position: relative;
        }

        nav a {
            width: calc(100% / 4);
            text-align: center;
            padding: 10px 0;
            text-decoration: none;
            font-size: 18px;
            color: #fff;
            position: relative;
            z-index: 1;
        }
        
        nav .bg {
            position: absolute;
            top: 0;
            bottom: 0;
            width: calc(100% / 4);
            left: 0;
            background-color: rgba(0,0,0,0.2);
            border-radius: 5px;
            transition: 0.2s all cubic-bezier(0.175, 0.885, 0.32, 1.275);
        }

        nav a:hover:nth-child(1) ~ .bg {
            left: 0;
        }

        nav a:hover:nth-child(2) ~ .bg {
            left: calc(100% / 4);
        }

        nav a:hover:nth-child(3) ~ .bg {
            left: calc((100% / 4) * 2);
        }

        nav a:hover:nth-child(4) ~ .bg {
            left: calc((100% / 4) * 3);
        }
    </style>
</head>
<body>
    <section>
        <nav>
            <a href="">Home</a>
            <a href="">About Us</a>
            <a href="">Services</a>
            <a href="">Contact Us</a>
            <div class="bg"></div>
        </nav>
    </section>
</body>
</html>

Result Screenshot(s)

Menubar with Moving HoverWorking Sample0