/**
 * Chess Academy — Navigation
 *
 * Desktop top nav, mobile hamburger, responsive behavior.
 */

.site-header {
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    border-bottom: 1px solid var(--color-border-light);
    background: var(--color-header-bg);
    backdrop-filter: saturate(180%) blur(14px);
    -webkit-backdrop-filter: saturate(180%) blur(14px);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 4rem;
    gap: var(--space-4);
}

/* Logo */
.nav__logo {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    font-size: var(--text-lg);
    font-weight: var(--weight-bold);
    color: var(--color-text);
    text-decoration: none;
    flex-shrink: 0;
}

.nav__logo:hover {
    color: var(--color-primary-500);
}

.nav__logo-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.25rem;
    height: 2.25rem;
    border-radius: var(--radius-md);
    background: linear-gradient(135deg, var(--color-primary-400), var(--color-primary-700));
    color: var(--color-text-inverse);
    font-size: 1.2rem;
    line-height: 1;
    box-shadow: var(--shadow-sm);
    flex-shrink: 0;
}

/* Nav links */
.nav__links {
    display: flex;
    align-items: center;
    gap: var(--space-1);
}

.nav__link {
    display: inline-flex;
    align-items: center;
    padding: var(--space-2) var(--space-3);
    font-size: var(--text-sm);
    font-weight: var(--weight-medium);
    color: var(--color-text-secondary);
    border-radius: var(--radius-md);
    transition: all var(--duration-fast) var(--ease-out);
    text-decoration: none;
}

.nav__link:hover {
    color: var(--color-text);
    background: var(--color-surface-alt);
}

.nav__link--active {
    color: var(--color-primary-500);
    background: var(--color-primary-50);
}

/* Nav actions */
.nav__actions {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    flex-shrink: 0;
}

.nav__logout-form {
    display: inline;
}

/* Hamburger */
.nav__hamburger {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 2.75rem;
    height: 2.75rem;
    padding: 0.5rem;
    border: none;
    background: none;
    cursor: pointer;
}

.nav__hamburger-line {
    display: block;
    width: 100%;
    height: 2px;
    background: var(--color-text);
    border-radius: 1px;
    transition: all var(--duration-normal) var(--ease-out);
    transform-origin: center;
}

.nav__hamburger--active .nav__hamburger-line:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.nav__hamburger--active .nav__hamburger-line:nth-child(2) {
    opacity: 0;
}

.nav__hamburger--active .nav__hamburger-line:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ── Mobile Responsive ────────────────────────────────────── */
@media (max-width: 1023px) {
    .nav__hamburger {
        display: flex;
    }

    .nav__links {
        display: none;
        position: absolute;
        top: 4rem;
        left: 0;
        right: 0;
        flex-direction: column;
        align-items: stretch;
        background: var(--color-surface);
        border-bottom: 1px solid var(--color-border);
        padding: var(--space-3);
        box-shadow: var(--shadow-lg);
    }

    .nav__links--open {
        display: flex;
    }

    .nav__link {
        padding: var(--space-3) var(--space-4);
    }

    .nav__actions .btn {
        font-size: var(--text-xs);
        padding: 0.25rem 0.5rem;
    }
}

@media (max-width: 480px) {
    .nav__logo-text {
        display: none;
    }
}