* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 10px;
    font-family: "Roboto Cn", sans-serif;
}

a {
    text-decoration: none;
    color: #eee;
}

header {
    width: 100%;
    height: 100vh;
    background: linear-gradient(to bottom, rgba(0, 0, 0, .8), rgba(0, 0, 0, .5)), url("https://yp.scmp.com/sites/default/files/styles/900x506/public/images/shutterstock_701721763.jpg") center no-repeat;
    background-size: cover;
    position: fixed;
    overflow: hidden;
}

.container {
    max-width: 120rem;
    width: 90%;
    margin: 0 auto;
}

.menu-toggle {
    position: fixed;
    top: 2.5rem;
    right: 2.5rem;
    color: #eee;
    font-size: 3rem;
    cursor: pointer;
    z-index: 1000;
    display: none;
}

nav {
    padding-top: 5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    text-transform: uppercase;
    font-size: 1.6rem;
}

.brand {
    color: skyblue;
    font-size: 3rem;
    font-weight: 300;
    transform: translateX(-100rem);
    animation: slideIn .5s forwards;
}

.brand span {
    color: rosybrown;
}

nav ul {
    display: flex;
}

nav ul li {
    list-style: none;
    transform: translateX(100rem);
    animation: slideIn .5s forwards;
}

nav ul li:nth-child(1) {
    animation-delay: 0s;
}

nav ul li:nth-child(2) {
    animation-delay: .3s;
}

nav ul li:nth-child(3) {
    animation-delay: 0.6s;
}

nav ul li:nth-child(4) {
    animation-delay: 0.9s;
}

nav ul li a {
    padding: 1rem 0;
    margin: 0 3rem;
    position: relative;
    letter-spacing: 2px;
}

nav ul li a:last-child {
    margin-right: 0;
}

nav ul li a::before,
nav ul li a::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 2px;
    background-color: whitesmoke;
    left: 0;
    transform: scaleX(0);
    transition: all .5s;
}

nav ul li a::before {
    top: 0;
    transform-origin: left;
}

nav ul li a::after {
    bottom: 0;
    transform-origin: right;
}

.overlay {
    background-color: rgba(0, 0, 0, .85);
    position: fixed;
    right: 0;
    left: 0;
    top: 0;
    bottom: 0;
    transition: opacity 650ms;
    transform: scale(0);
    opacity: 0;
    display: none;
}

nav ul li a:hover::before,
nav ul li a:hover::after {
    transform: scaleX(1);
}

@keyframes slideIn {
    from {}
    to {
        transform: translateX(0);
    }
}

@media screen and (max-width: 700px) {
    .menu-toggle {
        display: block;
    }
    nav {
        padding-top: 0;
        display: none;
        flex-direction: column;
        justify-content: space-evenly;
        align-items: center;
        height: 100vh;
        text-align: center;
    }
    nav ul {
        flex-direction: column;
    }
    nav ul li {
        margin-top: 5rem;
    }
    nav ul li a {
        margin: 0;
        font-size: 2.5rem;
    }
    .brand {
        font-size: 5rem;
    }
    .overlay.menu-open,
    nav.menu-open {
        display: flex;
        transform: scale(1);
        opacity: 1;
    }
}