index.html

<!DOCTYPE html> 
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>

    <style>
        @import url('https://fonts.googleapis.com/css2?family=Kanit:ital,wght@0,100;0,200;0,300;0,400;0,500;0,600;0,700;0,800;0,900;1,100;1,200;1,300;1,400;1,500;1,600;1,700;1,800;1,900&family=Lato:ital,wght@0,100;0,300;0,400;0,700;0,900;1,100;1,300;1,400;1,700;1,900&display=swap');
        * {
            margin: 0;
            padding: 0;
            font-family: "Lato", sans-serif;
        }

        main {

            height: 100vh;
            width: 100%;
            background-color: #014179;
            ;

        }

        nav {
            min-height: 70px;
            width: 100%;
            background-color: rgb(255, 255, 255);

        }

        .logo {

            float: left;
            padding: 20px;
            /* font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif; */
        }

        .left {
            text-align: right;
        }

        span {
            display: none;
        }

        ul li {

            list-style: none;
            display: inline-block;
            padding: 25px 20px;
            /* font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif; */
        }


        @media only screen and (max-width:540px) {

            span {
                display: block;
                text-align: right;
                padding: 20px;
                font-size: 22px;
                cursor: pointer;
            }

            ul li {
                display: block;
            }

            ul {
                display: none;

            }
            .left{
                text-align: left;
            }
        }
    </style>


    <main>
        <nav>

            <h1 class="logo">Java</h1>

            <span onclick="foo()">&#9776;</span>

            <div class="left">

                <ul id="list">

                    <li>Home</li>

                    <li>About</li>

                    <li>Services</li>

                    <li>Contact </li>

                    <li>Blog</li>
                </ul>

            </div>
        </nav>
    </main>


    <script>

        let list = document.getElementById('list');


        function foo() {

            if (list.style.display == 'none') {

                list.style.display = 'block'

            } else {

                list.style.display = 'none'
            }
        }

    </script>
</body>

</html>