@media(max-width: 600px) {
    #checkbtn {
        display: block;
        font-size: 40px;
        margin-right: 15px;
    }

    nav ul {
        width: 100%;
        height: 100vh;
        background-color: red;
        position: fixed;
        top: 80px;
        left: -100%;
        transition: .5s;
        padding-top: 10px;
        font-weight: bold;
    }

    nav ul li a:hover {
        background-color: white;
    }

    nav ul li {
        display: block;
        text-align: center;
    }
    
}