/* ==========================================================================
   HEADER STYLES
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: background var(--transition-fast);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
}

.header-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  gap: var(--space-4);
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-display);
  font-weight: var(--font-weight-bold);
  font-size: var(--text-xl);
  color: var(--color-text-primary);
  text-decoration: none;
  flex-shrink: 0;
}

.logo-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--color-accent-blue), var(--color-accent-purple));
  border-radius: var(--radius-md);
  color: var(--color-bg-primary);
  font-size: var(--text-lg);
}

.logo-text {
  background: linear-gradient(90deg, var(--color-text-primary) 0%, var(--color-accent-blue) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Navigation */
.primary-nav {
  flex: 1;
  display: flex;
  justify-content: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-link {
  display: block;
  padding: var(--space-2) var(--space-4);
  font-family: var(--font-display);
  font-weight: var(--font-weight-semibold);
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  text-decoration: none;
  border-radius: var(--radius-md);
  transition: color var(--transition-fast), background var(--transition-fast), box-shadow var(--transition-fast);
  text-transform: uppercase;
  letter-spacing: 0.02em;
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--color-accent-blue);
  background: rgba(0, 102, 204, 0.1);
  box-shadow: 0 0 15px rgba(0, 102, 204, 0.15);
  outline: none;
}

/* Header Actions */
.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.icon-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  color: var(--color-text-secondary);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  background: transparent;
  border: 1px solid transparent;
}

.icon-btn:hover,
.icon-btn:focus-visible {
  color: var(--color-accent-cyan);
  background: var(--color-bg-tertiary);
  border-color: var(--color-border-hover);
  outline: none;
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 44px;
  height: 44px;
  gap: 6px;
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: border-color var(--transition-fast);
}

.mobile-menu-toggle:hover,
.mobile-menu-toggle:focus-visible {
  border-color: var(--color-accent-blue);
  outline: none;
}

.hamburger-line {
  display: block;
  width: 24px;
  height: 2px;
  background: currentColor;
  color: var(--color-text-primary);
  border-radius: 2px;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

/* Mobile Styles */
@media (max-width: 768px) {
  .mobile-menu-toggle {
    display: flex;
    order: 3;
  }

  .primary-nav {
    position: fixed;
    top: 72px;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--color-bg-primary);
    flex-direction: column;
    justify-content: flex-start;
    padding: var(--space-6);
    transform: translateX(100%);
    transition: transform var(--transition-base);
    overflow-y: auto;
  }

  .primary-nav.is-open {
    transform: translateX(0);
    height: 100vh;
  }

  .nav-list {
    flex-direction: column;
    width: 100%;
    gap: var(--space-2);
  }

  .nav-link {
    width: 100%;
    padding: var(--space-4);
    font-size: var(--text-lg);
    border-bottom: 1px solid var(--color-border);
    border-radius: 0;
  }

  .mobile-menu-toggle[aria-expanded="true"] .hamburger-line:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
  }

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

  .mobile-menu-toggle[aria-expanded="true"] .hamburger-line:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
  }
}

/* Focus Visible Support */
@media (prefers-reduced-motion: reduce) {
  .primary-nav {
    transition: none;
  }
}