* {
    box-sizing: border-box;
}
body {
    margin: 0;
    padding: 0;
    background-color: #434c50;
    background-size: cover;
}

.nav {
    height: 100px;
    width: 100%;
    background-color: #4d4d4d;
    position: relative;
}

    .nav > .nav-header {
        display: inline;
    }

        .nav > .nav-header > .nav-title {
            display: inline-block;
            font-size: 22px;
            color: #fff;
            padding: 10px 10px 10px 10px;
        }

    .nav > .nav-btn {
        display: none;
    }

    .nav > .nav-links {
        display: inline;
        float: right;
        font-size: 18px;
    }

        .nav > .nav-links > a {
            display: inline-block;
            padding: 13px 10px 13px 10px;
            text-decoration: none;
            color: #efefef;
        }

            .nav > .nav-links > a:hover {
                background-color: rgba(0, 0, 0, 0.3);
            }

    .nav > #nav-check {
        display: none;
    }

@media (max-width:600px) {
    .nav > .nav-btn {
        display: inline-block;
        position: absolute;
        right: 0px;
        top: 0px;
    }

        .nav > .nav-btn > label {
            display: inline-block;
            width: 50px;
            height: 50px;
            padding: 13px;
        }

            .nav > .nav-btn > label:hover, .nav #nav-check:checked ~ .nav-btn > label {
                background-color: rgba(0, 0, 0, 0.3);
            }

            .nav > .nav-btn > label > span {
                display: block;
                width: 25px;
                height: 10px;
                border-top: 2px solid #eee;
            }

    .nav > .nav-links {
        position: absolute;
        display: block;
        width: 100%;
        background-color: #333;
        height: 0px;
        transition: all 0.3s ease-in;
        overflow-y: hidden;
        top: 50px;
        left: 0px;
    }

        .nav > .nav-links > a {
            display: block;
            width: 100%;
        }

    .nav > #nav-check:not(:checked) ~ .nav-links {
        height: 0px;
    }

    .nav > #nav-check:checked ~ .nav-links {
        height: calc(100vh - 50px);
        overflow-y: auto;
    }
}