/* ============================================================
   HEADER — Fixed nav, hamburger, mobile menu
   ============================================================ */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--nav-height);
  background-color: rgba(10, 7, 20, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-soft);
  transition: box-shadow var(--transition-base);
}

.site-header.scrolled {
  box-shadow: 0 2px 24px rgba(0, 0, 0, 0.5);
}

.site-header .container {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* ---------- Logo ---------- */
.site-logo {
  display: flex;
  align-items: center;
  flex-shrink: 0;
  text-decoration: none;
}

.site-logo img {
  height: 40px;
  width: auto;
}

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

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.nav-links a {
  font-family: var(--font-heading);
  font-size: var(--size-sm);
  font-weight: var(--weight-semibold);
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  letter-spacing: 0.02em;
  padding: var(--space-2) 0;
  position: relative;
  transition: color var(--transition-fast);
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-accent);
  border-radius: var(--radius-full);
  transition: width var(--transition-base);
}

.nav-links a:hover {
  color: var(--color-body);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

.nav-links a.active {
  color: var(--color-body);
}

/* ---------- Nav CTA ---------- */
.nav-cta {
  flex-shrink: 0;
}

/* ---------- Hamburger ---------- */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: var(--space-2);
  cursor: pointer;
  background: none;
  border: none;
  border-radius: var(--radius-md);
  transition: background-color var(--transition-fast);
}

.hamburger:hover {
  background-color: rgba(255,255,255,0.08);
}

.hamburger__bar {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-body);
  border-radius: var(--radius-full);
  transition: transform var(--transition-base), opacity var(--transition-base);
}

/* Hamburger → X */
.hamburger[aria-expanded="true"] .hamburger__bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.hamburger[aria-expanded="true"] .hamburger__bar:nth-child(2) {
  opacity: 0;
}

.hamburger[aria-expanded="true"] .hamburger__bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ---------- Mobile Menu ---------- */
.mobile-menu {
  display: none;
  position: fixed;
  top: var(--nav-height);
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(10, 7, 20, 0.97);
  padding: var(--space-8) var(--space-6);
  overflow-y: auto;
  opacity: 0;
  transform: translateY(-8px);
  transition: opacity var(--transition-base), transform var(--transition-base);
  pointer-events: none;
  z-index: 999;
}

.mobile-menu.is-open {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}

.mobile-nav-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin-bottom: var(--space-8);
}

.mobile-nav-links a {
  display: block;
  font-family: var(--font-heading);
  font-size: var(--size-lg);
  font-weight: var(--weight-semibold);
  color: rgba(255, 255, 255, 0.8);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--color-border);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.mobile-nav-links a:hover,
.mobile-nav-links a.active {
  color: var(--color-accent);
}

.mobile-menu .btn {
  width: 100%;
  justify-content: center;
}

/* ---------- Body lock when menu open ---------- */
body.menu-open {
  overflow: hidden;
}

/* ---------- Responsive ---------- */
@media (max-width: 980px) {
  .site-nav .nav-links,
  .site-nav .nav-cta {
    display: none;
  }

  .hamburger {
    display: flex;
  }

  .mobile-menu {
    display: block;
  }
}