/* =============================================
   HEADER STYLES
   ============================================= */
.site-header {
  position: fixed;
  top: 0;
  right: 0;
  left: 0;
  z-index: 1000;
  height: 70px;
  background: rgba(10, 10, 10, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--clr-border);
  transition: background var(--dur-med) var(--ease-out),
              box-shadow var(--dur-med) var(--ease-out);
}

.site-header.is-scrolled {
  background: rgba(10, 10, 10, 0.97);
  box-shadow: 0 4px 24px rgba(0,0,0,0.4);
}

.header__inner {
  display: flex;
  align-items: center;
  height: 100%;
  gap: var(--sp-8);
}

/* --- Logo --- */
.header__logo {
  flex-shrink: 0;
  text-decoration: none;
}

.logo-text {
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--clr-white);
  letter-spacing: -0.02em;
}

.logo-text__ai {
  color: var(--clr-orange);
}

/* --- Desktop Nav --- */
.header__nav {
  flex: 1;
  display: flex;
  justify-content: center;
}

.nav__list {
  display: flex;
  align-items: center;
  gap: var(--sp-1);
}

.nav__list li a {
  display: block;
  padding: var(--sp-2) var(--sp-3);
  color: var(--clr-text-muted);
  font-size: var(--text-sm);
  font-weight: 500;
  border-radius: var(--radius-sm);
  transition: color var(--dur-fast) var(--ease-out),
              background var(--dur-fast) var(--ease-out);
}

.nav__list li a:hover,
.nav__list li.current-menu-item > a {
  color: var(--clr-white);
  background: var(--clr-surface-2);
}

.nav__list li.current-menu-item > a {
  color: var(--clr-orange);
}

/* --- Actions --- */
.header__actions {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  gap: var(--sp-3);
}

.btn--sm {
  padding: var(--sp-2) var(--sp-4);
  font-size: var(--text-sm);
}

/* --- Hamburger --- */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 28px;
  height: 20px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}

.hamburger span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--clr-white);
  border-radius: 2px;
  transition: transform var(--dur-med) var(--ease-out),
              opacity var(--dur-med) var(--ease-out);
}

.hamburger.is-active span:nth-child(1) {
  transform: translateY(9px) rotate(45deg);
}
.hamburger.is-active span:nth-child(2) {
  opacity: 0;
}
.hamburger.is-active span:nth-child(3) {
  transform: translateY(-9px) rotate(-45deg);
}

/* --- Mobile Nav --- */
.mobile-nav {
  position: fixed;
  top: 70px;
  right: 0;
  left: 0;
  background: rgba(10, 10, 10, 0.97);
  border-bottom: 1px solid var(--clr-border);
  padding: var(--sp-4);
  transform: translateY(-110%);
  opacity: 0;
  transition: transform var(--dur-med) var(--ease-out),
              opacity var(--dur-med) var(--ease-out);
  pointer-events: none;
}

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

.mobile-nav__list {
  display: flex;
  flex-direction: column;
  gap: var(--sp-1);
}

.mobile-nav__list li a {
  display: block;
  padding: var(--sp-3) var(--sp-4);
  color: var(--clr-text);
  font-size: var(--text-base);
  font-weight: 500;
  border-radius: var(--radius-sm);
  transition: color var(--dur-fast), background var(--dur-fast);
}

.mobile-nav__list li a:hover {
  color: var(--clr-orange);
  background: var(--clr-surface);
}

/* push content below fixed header */
.site-main {
  padding-top: 70px;
}

/* =============================================
   RESPONSIVE
   ============================================= */
@media (max-width: 768px) {
  .header__nav { display: none; }
  .header__actions .btn--primary { display: none; }
  .hamburger { display: flex; }
}