/* ==========================================================================
   Header & Navigation
   ========================================================================== */

.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--header-height);
  z-index: 100;
  transition: background-color var(--transition-base), box-shadow var(--transition-base);
}

.header--transparent {
  background-color: transparent;
}

.header--scrolled {
  background-color: #fff;
  box-shadow: var(--shadow-md);
}

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

/* Logo */
.header__logo {
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  letter-spacing: var(--letter-spacing-wide);
  text-transform: uppercase;
  color: #fff;
  transition: color var(--transition-base);
}

.header--scrolled .header__logo {
  color: var(--color-primary-900);
}

.header__logo span {
  font-weight: var(--font-weight-regular);
  opacity: 0.7;
}

/* Desktop Navigation */
.nav {
  display: none;
  align-items: center;
  gap: var(--space-8);
}

.nav__link {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: rgba(255, 255, 255, 0.8);
  transition: color var(--transition-fast);
  padding: var(--space-2) 0;
  position: relative;
}

.nav__link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: currentColor;
  transition: width var(--transition-base);
}

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

.nav__link:hover {
  color: #fff;
}

.header--scrolled .nav__link {
  color: var(--color-neutral-600);
}

.header--scrolled .nav__link:hover,
.header--scrolled .nav__link--active {
  color: var(--color-primary-700);
}

/* Non-transparent header pages (inner pages) */
.header--solid {
  background-color: var(--color-primary-900);
}

.header--solid.header--scrolled {
  background-color: #fff;
}

/* Mobile Hamburger */
.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 10px;
}

.nav-toggle__bar {
  display: block;
  width: 24px;
  height: 2px;
  background: #fff;
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-fast);
}

.header--scrolled .nav-toggle__bar {
  background: var(--color-primary-900);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

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

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* Mobile Menu */
.nav-mobile {
  position: fixed;
  top: var(--header-height);
  left: 0;
  width: 100%;
  background: #fff;
  box-shadow: var(--shadow-lg);
  padding: var(--space-6);
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  transform: translateY(-100%);
  opacity: 0;
  visibility: hidden;
  transition: transform var(--transition-base), opacity var(--transition-base), visibility var(--transition-base);
  z-index: 99;
}

.nav-mobile.is-open {
  transform: translateY(0);
  opacity: 1;
  visibility: visible;
}

.nav-mobile__link {
  display: block;
  padding: var(--space-3) var(--space-4);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  color: var(--color-neutral-700);
  border-radius: var(--radius-md);
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.nav-mobile__link:hover,
.nav-mobile__link--active {
  background-color: var(--color-primary-50);
  color: var(--color-primary-700);
}

/* Mobile menu overlay */
.nav-overlay {
  position: fixed;
  inset: 0;
  background: rgba(10, 22, 40, 0.3);
  z-index: 98;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-base), visibility var(--transition-base);
}

.nav-overlay.is-open {
  opacity: 1;
  visibility: visible;
}