/* ================================
   Navigation Component
   ================================ */

.header {
  position: sticky;
  top: 0;
  z-index: var(--z-index-sticky);
  background-color: var(--color-bg-overlay);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  transition: var(--transition-colors);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) var(--space-6);
  max-width: var(--container-xl);
  margin: 0 auto;
}

/* Logo/Site Title */
.site-title {
  font-family: var(--font-family-heading);
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-black);
  letter-spacing: 0.02em;
  margin: 0;
}

.site-title a {
  color: var(--color-text-primary);
  transition: var(--transition-colors);
}

.site-title a:hover {
  color: var(--color-accent-primary);
}

/* Navigation Links */
.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-8);
  list-style: none;
  margin: 0;
}

.nav-links a {
  color: var(--color-text-secondary);
  font-weight: var(--font-weight-medium);
  font-size: var(--font-size-sm);
  letter-spacing: var(--letter-spacing-wide);
  text-transform: uppercase;
  position: relative;
  padding: var(--space-3) 0;
  transition: var(--transition-colors);
  line-height: 1.5;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent-primary);
  transition: width var(--duration-base) var(--ease-smooth);
}

.nav-links a:hover {
  color: var(--color-text-primary);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

.nav-links a.active {
  color: var(--color-accent-primary);
}

/* Theme Toggle Button */
.theme-toggle {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-full);
  background-color: var(--color-bg-tertiary);
  border: 1px solid var(--color-border);
  cursor: pointer;
  transition: var(--transition-all);
  margin-left: var(--space-4);
  position: relative;
}

.theme-toggle:hover {
  background-color: var(--color-accent-primary);
  border-color: var(--color-accent-primary);
  transform: scale(1.05);
}

.theme-toggle svg {
  width: 22px;
  height: 22px;
  stroke: var(--color-text-primary);
  fill: none;
  stroke-width: 2;
  stroke-linecap: round;
  stroke-linejoin: round;
  position: absolute;
  transition: opacity 0.2s ease, transform 0.2s ease, stroke 0.2s ease;
  opacity: 0;
  transform: rotate(0deg) scale(1);
}

.theme-toggle:hover svg {
  stroke: var(--color-text-inverse);
}

/* Icon visibility states managed by JavaScript */
.theme-toggle .icon-moon,
.theme-toggle .icon-sun {
  pointer-events: none;
}

/* Initial visibility for sun icon (dark mode default) */
.theme-toggle .icon-sun {
  opacity: 1;
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: none;
  width: 40px;
  height: 40px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  background: transparent;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
}

.mobile-menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--color-text-primary);
  transition: var(--transition-all);
  border-radius: var(--radius-full);
}

.mobile-menu-toggle.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.mobile-menu-toggle.active span:nth-child(2) {
  opacity: 0;
}

.mobile-menu-toggle.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile Menu Overlay */
.mobile-menu {
  position: fixed;
  top: 0;
  right: -100%;
  width: 100%;
  max-width: 400px;
  height: 100vh;
  background-color: var(--color-bg-overlay);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  padding: var(--space-20) var(--space-8);
  transition: right var(--duration-base) var(--ease-smooth);
  z-index: var(--z-index-modal);
  overflow-y: auto;
}

.mobile-menu.active {
  right: 0;
}

.mobile-menu-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100vh;
  background-color: rgba(0, 0, 0, 0.5);
  opacity: 0;
  visibility: hidden;
  transition: var(--transition-all);
  z-index: calc(var(--z-index-modal) - 1);
}

.mobile-menu-backdrop.active {
  opacity: 1;
  visibility: visible;
}

.mobile-nav-links {
  list-style: none;
  margin: 0;
  padding: 0;
}

.mobile-nav-links li {
  margin-bottom: var(--space-4);
}

.mobile-nav-links a {
  display: block;
  color: var(--color-text-primary);
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-semibold);
  padding: var(--space-3) 0;
  transition: var(--transition-colors);
}

.mobile-nav-links a:hover {
  color: var(--color-accent-primary);
  padding-left: var(--space-2);
}

/* Responsive */
@media (max-width: 768px) {
  .nav-container {
    padding: var(--space-3) var(--space-4);
  }

  .nav-links {
    display: none;
  }

  .mobile-menu-toggle {
    display: flex;
  }

  .site-title {
    font-size: var(--font-size-lg);
  }
}