/* Site header and responsive navigation. */

/* Header shell */
.header {
    --header-surface: rgba(255, 255, 255, 0.07);
    --header-surface-soft: rgba(255, 255, 255, 0.03);
    --header-logo-height: clamp(40px, calc((146px + 15vw) / 5), 70px);
    --header-nav-gap: clamp(6px, calc((12px + 5vw) / 5), 16px);
    --header-control-size: calc(var(--icon-s) + var(--space-s) + var(--space-s));
    background: var(--shell-bg-gradient-x);
}

.header__inner {
    display: flex;
    max-width: var(--page-container);
    margin: 0 auto;
    padding: var(--header-nav-gap);
    align-items: center;
    gap: var(--header-nav-gap);
}

.header__logo {
    flex: 0 0 auto;
    margin-right: auto;
}

.header__logo a {
    display: inline-flex;
    align-items: center;
}

.header__logo img {
    height: var(--header-logo-height);
    transform-origin: center;
    transition: transform var(--transition-medium), filter 0s;
}

/* Primary navigation */
.header__nav {
    display: flex;
    align-items: center;
    justify-content: flex-end;
    gap: var(--header-nav-gap);
}

.header__link, .header__dropdown-toggle, .header__icon-button {
    color: var(--shell-text);
    line-height: 1;
    font-size: clamp(1rem, calc((30.1rem + 4vw) / 31), 1.1rem);
    font-weight: 600;
    letter-spacing: 0.04em;
    text-decoration: none;
    white-space: nowrap;
    transition: color var(--transition-medium), background-color var(--transition-medium);
}

.header__link.is-active,
.header__dropdown-toggle.is-active,
.header__menu-option.is-active {
    color: var(--shell-accent);
    text-decoration: underline;
    text-decoration-color: var(--shell-accent);
    text-decoration-thickness: 2px;
    text-underline-offset: 6px;
}

.header [data-dropdown] {
    position: relative;
    padding-bottom: var(--space-s);
    margin-bottom: calc(-1 * var(--space-s));
}

.header__dropdown-toggle {
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

/* Header controls */
.header__icon-button {
    display: inline-flex;
    min-width: var(--header-control-size);
    min-height: var(--header-control-size);
    padding: var(--space-s);
    align-items: center;
    justify-content: center;
    gap: 6px;
    border-radius: var(--radius-s);
}

.header__dropdown.is-open .header__dropdown-toggle {
    color: var(--shell-accent);
}

.header__language.is-open .header__icon-button {
    background: var(--header-surface);
}

.header__icon {
    display: block;
    flex: 0 0 auto;
    width: var(--icon-s);
    height: auto;
    max-height: var(--icon-s);
}

.header__theme-icon--moon {
    display: block;
}

.header__theme-icon--sun {
    display: none;
}

html[data-theme="dark"] .header__theme-icon--sun {
    display: block;
}

html[data-theme="dark"] .header__theme-icon--moon {
    display: none;
}

.header__arrow {
    flex: 0 0 auto;
    width: 0;
    height: 0;
    border-right: 5px solid transparent;
    border-left: 5px solid transparent;
    border-top: 6px solid var(--shell-text);
    transition: transform var(--transition-medium), border-top-color var(--transition-medium);
}

.header [data-dropdown].is-open .header__arrow {
    transform: rotate(180deg);
    border-top-color: var(--shell-accent);
}

/* Dropdown menus */
.header__menu {
    display: none;
    position: absolute;
    top: 100%;
    min-width: 220px;
    max-width: calc(100vw - 32px);
    overflow: hidden;
    background: var(--shell-bg-gradient-y);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-s);
    box-shadow: 0 0 24px rgba(0, 0, 0, 0.42);
    z-index: 1000;
}

.header__dropdown .header__menu {
    left: 0;
}

.header__language .header__menu {
    right: 0;
}

.header [data-dropdown].is-open .header__menu {
    display: block;
}

.header__menu-option {
    display: flex;
    padding: 10px;
    align-items: center;
    gap: 10px;
    color: var(--shell-text);
    text-decoration: none;
    white-space: nowrap;
    transition: color var(--transition-medium), background-color var(--transition-medium);
}

/* Mobile menu toggle */
.header__mobile-toggle {
    display: none;
    position: relative;
    flex: 0 0 auto;
    width: var(--header-control-size);
    height: var(--header-control-size);
    border: 1px solid rgba(255, 255, 255, 0.14);
    border-radius: var(--radius-s);
    background: var(--header-surface);
    color: var(--shell-text);
}

.header__mobile-toggle span,
.header__mobile-toggle span::before,
.header__mobile-toggle span::after {
    content: "";
    position: absolute;
    top: 50%;
    left: 50%;
    width: 22px;
    height: 2px;
    border-radius: var(--radius-pill);
    background: currentColor;
    transform: translate(-50%, -50%);
    transition: transform var(--transition-medium), opacity var(--transition-medium), background-color var(--transition-medium);
}

.header__mobile-toggle span::before {
    transform: translate(-50%, calc(-50% - 7px));
}

.header__mobile-toggle span::after {
    transform: translate(-50%, calc(-50% + 7px));
}

.header.is-nav-open .header__mobile-toggle {
    color: var(--shell-accent);
}

.header.is-nav-open .header__mobile-toggle span {
    background: transparent;
}

.header.is-nav-open .header__mobile-toggle span::before {
    transform: translate(-50%, -50%) rotate(45deg);
}

.header.is-nav-open .header__mobile-toggle span::after {
    transform: translate(-50%, -50%) rotate(-45deg);
}

/* Desktop hover states */
@media (width >= 980px) and (any-hover: hover) and (any-pointer: fine) {
    .header__logo a:hover img {
        transform: scale(1.1);
        filter: brightness(1.1);
    }

    .header__link:hover,
    .header__dropdown-toggle:hover,
    .header__dropdown:hover .header__dropdown-toggle,
    .header__menu-option:hover {
        color: var(--shell-accent);
    }

    .header__icon-button:hover, .header__menu-option:hover {
        background: var(--header-surface);
    }
}

/* Responsive navigation */
@media (width < 980px) {
    .header__inner {
        flex-wrap: wrap;
    }

    .header__logo {
        order: 1;
    }

    .header__mobile-toggle {
        display: block;
        order: 2;
    }

    .header__theme-toggle {
        order: 3;
    }

    .header__language {
        order: 4;
    }

    .header__nav {
        display: none;
        order: 5;
        flex: 0 0 100%;
        width: 100%;
        padding: var(--radius-s) 0 4px;
        align-items: stretch;
        justify-content: flex-start;
        border-top: 1px solid rgba(255, 255, 255, 0.08);
    }

    .header.is-nav-open .header__nav {
        display: flex;
        flex-direction: column;
    }

    .header__link, .header__dropdown-toggle {
        display: flex;
        width: 100%;
        min-height: var(--header-control-size);
        padding: 10px var(--radius-s);
        align-items: center;
        justify-content: space-between;
        border-radius: var(--radius-s);
        background: var(--header-surface-soft);
    }

    :is(.header__link,
    .header__dropdown-toggle).is-active,
    .header__dropdown.is-open .header__dropdown-toggle {
        background: var(--header-surface);
    }

    .header__dropdown {
        display: block;
        width: 100%;
    }

    .header__dropdown .header__menu {
        position: static;
        width: 100%;
        min-width: 0;
        max-width: none;
        margin-top: var(--space-s);
        border-radius: var(--radius-m);
        background: var(--shell-bg-gradient-y);
        box-shadow: none;
    }
}