/* ============================================
   NAVIGATION
   Sticky Header with Glass Morphism
   ============================================ */

.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: var(--z-fixed);
  transition: all var(--duration-base) var(--ease-out);
  padding: var(--space-4) 0;
  background: var(--bg-primary);
  overflow: hidden;
  border-bottom: 1px solid var(--bg-primary);
}

@media (min-width: 768px) {
  .nav {
    background: transparent;
    overflow: visible;
    border-bottom: none;
  }
}

.nav::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 20px;
  background: linear-gradient(to bottom, var(--bg-primary) 0%, transparent 100%);
  pointer-events: none;
}

@media (min-width: 768px) {
  .nav::after {
    display: none;
  }
}

.nav.scrolled {
  background: var(--bg-glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
  box-shadow: var(--shadow-md);
}

.nav-container {
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: 0 var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: relative;
  z-index: 2;
  min-height: 60px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-weight: var(--font-bold);
  font-size: var(--text-xl);
  transition: transform var(--duration-base) var(--ease-out);
}

.nav-logo:hover {
  transform: scale(1.05);
}

.logo-icon {
  font-size: var(--text-2xl);
}

.logo-text {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: none !important;
  gap: var(--space-8);
  visibility: hidden;
  opacity: 0;
  height: 0;
  overflow: hidden;
}

@media (min-width: 768px) {
  .nav-links {
    display: flex !important;
    visibility: visible;
    opacity: 1;
    height: auto;
  }
}

.nav-link {
  font-weight: var(--font-medium);
  position: relative;
  transition: color var(--duration-base) var(--ease-out);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--gradient-primary);
  transition: width var(--duration-base) var(--ease-out);
}

.nav-link:hover::after {
  width: 100%;
}

.nav-buttons {
  display: none;
  gap: var(--space-3);
  align-items: center;
}

@media (min-width: 768px) {
  .nav-buttons {
    display: flex;
  }
}

.btn-nav {
  display: inline-flex;
}

/* Mobile Menu Button */
.mobile-menu-button {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: var(--space-2);
  cursor: pointer;
  background: none;
  border: none;
}

@media (min-width: 768px) {
  .mobile-menu-button {
    display: none;
  }
}

.hamburger {
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  transition: all var(--duration-base) var(--ease-out);
}

.hamburger::before,
.hamburger::after {
  content: '';
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  transition: all var(--duration-base) var(--ease-out);
}

.hamburger::before {
  transform: translateY(-8px);
}

.hamburger::after {
  transform: translateY(6px);
}

.mobile-menu-button.active .hamburger {
  background: transparent;
}

.mobile-menu-button.active .hamburger::before {
  transform: rotate(45deg);
}

.mobile-menu-button.active .hamburger::after {
  transform: rotate(-45deg) translateY(0);
}

/* Mobile Menu */
.mobile-menu {
  display: none;
  flex-direction: column;
  gap: var(--space-4);
  padding: 0;
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-subtle);
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--duration-slow) var(--ease-out);
  visibility: hidden;
  opacity: 0;
}

.mobile-menu.open {
  display: flex;
  max-height: 400px;
  padding: var(--space-6);
  visibility: visible;
  opacity: 1;
}

@media (min-width: 768px) {
  .mobile-menu {
    display: none !important;
  }
}

.mobile-nav-link {
  font-weight: var(--font-medium);
  padding: var(--space-3);
  border-radius: var(--radius-md);
  transition: background var(--duration-base) var(--ease-out);
}

.mobile-nav-link:hover {
  background: var(--bg-elevated);
}

.mobile-menu-buttons {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  margin-top: var(--space-4);
  padding-top: var(--space-4);
  border-top: 1px solid var(--border-subtle);
}