/* ═══════════════════════════════════════════════════════════
   Header / Navigation
   ═══════════════════════════════════════════════════════════ */

.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: var(--z-header);
    padding: var(--space-4) 0;
    transition: all var(--duration-base) var(--ease-out);
    background: transparent;
}

.header--scrolled {
    background: rgba(10, 10, 15, 0.85);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-3) 0;
}

.header__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

/* ── Logo ── */
.header__logo {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    z-index: calc(var(--z-header) + 1);
}

.logo__icon {
    font-family: var(--font-mono);
    font-size: var(--text-lg);
    font-weight: 700;
    color: var(--color-accent-light);
    background: rgba(99, 102, 241, 0.1);
    border: 1px solid rgba(99, 102, 241, 0.2);
    border-radius: var(--radius-md);
    padding: var(--space-1) var(--space-2);
    line-height: 1;
}

.logo__text {
    font-size: var(--text-xl);
    font-weight: 700;
    letter-spacing: -0.02em;
}

.logo__accent {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* ── Nav ── */
.header__nav {
    display: flex;
    align-items: center;
    gap: var(--space-8);
}

.nav__link {
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-text-secondary);
    position: relative;
    padding: var(--space-2) 0;
}

.nav__link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
    transition: width var(--duration-base) var(--ease-out);
}

.nav__link:hover,
.nav__link--active {
    color: var(--color-text);
}

.nav__link:hover::after,
.nav__link--active::after {
    width: 100%;
}

/* ── Burger ── */
.header__burger {
    display: none;
    flex-direction: column;
    gap: 5px;
    width: 28px;
    padding: 4px 0;
    z-index: calc(var(--z-header) + 1);
}

.header__burger span {
    display: block;
    height: 2px;
    background: var(--color-text);
    border-radius: var(--radius-full);
    transition: all var(--duration-base) var(--ease-out);
    transform-origin: center;
}

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

.header__burger.active span:nth-child(2) {
    opacity: 0;
    transform: scaleX(0);
}

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

/* ── Mobile menu ── */
@media (max-width: 768px) {
    .header__burger {
        display: flex;
    }

    .header__nav {
        position: fixed;
        top: 0;
        right: 0;
        width: min(320px, 85vw);
        height: 100vh;
        flex-direction: column;
        justify-content: center;
        gap: var(--space-8);
        background: rgba(10, 10, 15, 0.97);
        backdrop-filter: blur(30px);
        -webkit-backdrop-filter: blur(30px);
        border-left: 1px solid var(--color-border);
        transform: translateX(100%);
        transition: transform var(--duration-slow) var(--ease-out);
    }

    .header__nav.open {
        transform: translateX(0);
    }

    .nav__link {
        font-size: var(--text-xl);
    }
}