/**
 * Header Component — Premium-Premium v2.0
 * @package Stratos_One_Portfolio
 * 
 * Features:
 * - Sticky header with blur backdrop
 * - Premium spacing
 * - Scroll-based height reduction
 * - Enterprise CTA hierarchy
 */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-fixed);
  background-color: transparent;
  transition: all var(--transition-base);
  border-bottom: 1px solid transparent;
  height: var(--header-height, 80px);
}

.site-header.scrolled {
  background-color: rgba(7, 9, 12, 0.85);
  backdrop-filter: blur(16px) saturate(1.5);
  -webkit-backdrop-filter: blur(16px) saturate(1.5);
  border-bottom-color: var(--color-border-subtle);
  box-shadow: 0 1px 0 var(--color-border-subtle), 0 8px 32px rgba(0,0,0,0.4);
  height: var(--header-height-scrolled, 64px);
}

.site-header.scrolled .header-content {
  padding-top: 0;
  padding-bottom: 0;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 1.25rem var(--container-padding);
  height: var(--header-height, 80px);
  gap: var(--spacing-xl);
  transition: all var(--transition-base);
}

/* Branding */
.site-branding a {
  color: var(--color-text-primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 12px;
  transition: opacity var(--transition-fast), transform var(--transition-fast);
}

.site-branding a:hover {
  opacity: 0.85;
  transform: translateX(2px);
}

.brand-logo {
  width: auto;
  height: 40px;
  display: block;
  transition: height var(--transition-base);
}

.site-header.scrolled .brand-logo {
  height: 32px;
}

/* Nav */
.main-navigation ul {
  display: flex;
  gap: 4px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.main-navigation a {
  display: block;
  padding: 8px 16px;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  text-decoration: none;
  border-radius: var(--radius);
  transition: all var(--transition-fast);
  letter-spacing: -0.01em;
  position: relative;
}

.main-navigation a::after {
  content: '';
  position: absolute;
  bottom: 6px;
  left: 16px;
  right: 16px;
  height: 2px;
  background: var(--color-accent-primary);
  transform: scaleX(0);
  transition: transform var(--transition-fast);
  border-radius: 2px;
}

.main-navigation a:hover {
  color: var(--color-text-primary);
  background-color: var(--color-surface-subtle);
}

.main-navigation a:hover::after {
  transform: scaleX(1);
}

.main-navigation .current-menu-item a {
  color: var(--color-accent-primary);
  background-color: var(--color-surface-active);
}

.main-navigation .current-menu-item a::after {
  transform: scaleX(1);
}

/* Header CTAs — Enterprise Hierarchy */
.header-cta-group {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.header-cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 9px 18px;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  border-radius: var(--radius);
  text-decoration: none;
  transition: all var(--transition-base);
  white-space: nowrap;
  letter-spacing: -0.01em;
}

/* Secondary CTA (Outline) */
.header-cta-secondary {
  background-color: transparent;
  color: var(--color-text-secondary);
  border: 1px solid var(--color-border-strong);
}

.header-cta-secondary:hover {
  color: var(--color-text-primary);
  border-color: var(--color-accent-primary);
  background-color: var(--color-surface-subtle);
  transform: translateY(-1px);
}

/* Primary CTA (Filled) */
.header-cta-primary {
  background-color: var(--color-accent-primary);
  color: #fff;
  border: 1px solid transparent;
  box-shadow: 0 2px 12px rgba(59, 130, 246, 0.35);
}

.header-cta-primary:hover {
  background-color: var(--color-accent-hover);
  color: #fff;
  box-shadow: 0 6px 20px rgba(59, 130, 246, 0.45);
  transform: translateY(-2px);
}

/* Mobile toggle */
.menu-toggle {
  display: none;
  background: none;
  border: 1px solid var(--color-border-strong);
  color: var(--color-text-primary);
  cursor: pointer;
  padding: 8px 12px;
  border-radius: var(--radius);
  transition: all var(--transition-fast);
  font-size: 1.4rem;
  line-height: 1;
}

.menu-toggle-icon {
  display: block;
  font-size: 1.4rem;
  line-height: 1;
}

.menu-toggle:hover {
  border-color: var(--color-accent-primary);
  color: var(--color-accent-primary);
  background-color: var(--color-surface-active);
}

/* Responsive */
@media (max-width: 992px) {
  .header-cta-group { 
    display: none; 
  }
  
  .main-navigation a::after {
    display: none; /* Hide underline on mobile */
  }
}

@media (max-width: 768px) {
  .menu-toggle { 
    display: block; 
  }

  .main-navigation {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: rgba(7, 9, 12, 0.98);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border-subtle);
    padding: var(--spacing-md);
    display: none;
    max-height: 70vh;
    overflow-y: auto;
  }

  .main-navigation.active { 
    display: block; 
    animation: slideDown 0.2s ease-out;
  }

  .main-navigation ul {
    flex-direction: column;
    gap: 4px;
  }

  .main-navigation a {
    padding: 12px 16px;
  }

  .brand-logo { 
    height: 36px; 
  }

  .header-content { 
    height: 64px;
    padding: 1rem var(--container-padding);
  }
  
  .site-header.scrolled .header-content {
    height: 60px;
  }
}

@media (max-width: 480px) {
  .brand-logo { 
    height: 32px; 
  }
  
  .header-content { 
    padding: 0.875rem var(--spacing-md);
  }
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}