header {
    display: flex;
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
    padding: 20px var(--space-gutter);
    position: fixed;
    z-index: var(--z-fixed);
    width: 100%;
    backdrop-filter: blur(4px);
}

nav {
    display: flex;
    flex-direction: row;
    gap: 50px;
}

.header-button {
    position: relative;
    text-decoration: none;
    color: var(--color-text);
    font-size: 1rem;
    font-weight: 300;
}

.header-button::after {
    content: '';
    width: 0%;
    height: 1px;
    background: var(--color-text);
    position: absolute;
    left: 0;
    bottom: -4px;
    overflow: hidden;
    transition: all var(--duration-slow) var(--easing-base);
}

.header-button[state="current"]::after {
    content: '';
    width: 75%;
    height: 1px;
    background: var(--color-text);
    position: absolute;
    left: 0;
    bottom: -4px;
    overflow: hidden;
}

.header-button[state="current"] {
    font-weight: 300;
    font-size: 1.05rem;
}

.header-button[state="next"] {
    opacity: 0.7;
}

.header-button:hover::after {
    width: 75%;
}

.header-button:hover {
    opacity: 1;
}

.main-logo-link {
    flex: 1;
    display: block;
    line-height: 0;
}

.main-logo {
    height: 25px;
    width: auto;
}

header empty {
    flex: 1;
    display: block;
}

/* ===== Hamburger ===== */

.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    width: 28px;
    height: 28px;
}

.nav-toggle span {
    display: block;
    width: 22px;
    height: 1.5px;
    background: var(--color-text);
    transition: transform var(--duration-base) var(--easing-smooth), opacity var(--duration-fast) var(--easing-base);
    transform-origin: center;
}

header.nav-open .nav-toggle span:nth-child(1) {
    transform: translateY(6.5px) rotate(45deg);
}
header.nav-open .nav-toggle span:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
}
header.nav-open .nav-toggle span:nth-child(3) {
    transform: translateY(-6.5px) rotate(-45deg);
}

/* ===== Mobile ===== */

@media (max-width: 768px) {
    header {
        flex-wrap: wrap;
        padding: var(--space-sm) var(--space-sm);
        gap: 0;
        /* background: var(--color-bg); */
    }

    .nav-toggle {
        display: flex;
    }

    header empty {
        display: none;
    }

    nav {
        display: none;
        flex-direction: column;
        gap: 0;
        width: 100%;
        order: 3;
        padding: var(--space-sm) 0 var(--space-xs);
        border-top: 1px solid var(--color-border);
        margin-top: var(--space-sm);
    }

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

    .header-button {
        padding: var(--space-sm) 0;
        font-size: 1.05rem;
        border-bottom: 1px solid var(--color-border-subtle);
    }

    .header-button:last-child {
        border-bottom: none;
    }

    .header-button::after,
    .header-button[state="current"]::after {
        display: none;
    }
}