header {
    position: sticky;
    top: 0;
    background-color: var(--color-bg-sub);
}

header h2 {
    font-size: 1.2rem;
}

header .container {
    max-width: 1200px;
    margin: 0 auto;
}

nav {
    padding: 0 1rem;
    height: 60px;
}

.hamburger {
    display: none;
}

.hamburger .line {
    width: 20px;
    height: 2px;
    background-color: var(--color-text);
    display: block;
    margin: 3px auto;
    -webkit-transition: all var(--transition-base);
    -o-transition: all var(--transition-base);
    transition: all var(--transition-base);
}

.hamburger.is-active {
    -webkit-transition: all 0.3s ease-in-out;
    -o-transition: all 0.3s ease-in-out;
    transition: all 0.3s ease-in-out;
    -webkit-transition-delay: 0.6s;
    -o-transition-delay: 0.6s;
    transition-delay: 0.6s;
    -webkit-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    -o-transform: rotate(45deg);
    transform: rotate(45deg);
}

.hamburger.is-active .line:nth-child(2) {
    width: 0px;
}

.hamburger.is-active .line:nth-child(1),
.hamburger.is-active .line:nth-child(3) {
    -webkit-transition-delay: 0.3s;
    -o-transition-delay: 0.3s;
    transition-delay: 0.3s;
}

.hamburger.is-active .line:nth-child(1) {
    -webkit-transform: translateY(5px);
    -ms-transform: translateY(5px);
    -o-transform: translateY(5px);
    transform: translateY(5px);
}

.hamburger.is-active .line:nth-child(3) {
    -webkit-transform: translateY(-5px) rotate(90deg);
    -ms-transform: translateY(-5px) rotate(90deg);
    -o-transform: translateY(-5px) rotate(90deg);
    transform: translateY(-5px) rotate(90deg);
}

@media (max-width:480px) {
    .hamburger {
        display: block;
    }

    .nav-left {
        position: absolute;
        top: 60px;
        left: 0;
        right: 0;

        background: var(--color-bg-sub);
        flex-direction: column;
        padding: 1rem;

        display: none;
    }

    header.nav-open .nav-left {
        display: flex;
    }
}