/**
 * Header & Navigation
 * Modern responsive header with dropdown menus
 */

/* ===========================
   Header Base
   =========================== */

.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(--border-color);
  transition: all var(--transition-base);
}

[data-theme="dark"] .site-header {
  background: rgba(17, 24, 39, 0.95);
}

.site-header.scrolled {
  box-shadow: var(--shadow-md);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) 0;
  gap: var(--space-8);
}

/* ===========================
   Logo
   =========================== */

.logo-link {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  transition: transform var(--transition-fast);
}

.logo-link:hover {
  transform: scale(1.02);
}

.logo-icon {
  width: 40px;
  height: 40px;
  flex-shrink: 0;
}

.logo-text {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.logo-name {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--text-primary);
  line-height: 1;
  letter-spacing: -0.02em;
}

.logo-tagline {
  font-size: 0.625rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-tertiary);
  font-weight: 600;
}

/* ===========================
   Navigation Links (Desktop)
   =========================== */

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex: 1;
  justify-content: center;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-3);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  background: transparent;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
  text-decoration: none;
}

.nav-link:hover {
  color: var(--brand-600);
  background: var(--bg-secondary);
}

.nav-icon {
  width: 16px;
  height: 16px;
  transition: transform var(--transition-fast);
}

.nav-dropdown:hover .nav-icon,
.nav-dropdown.active .nav-icon {
  transform: rotate(180deg);
}

/* ===========================
   Dropdown Menus
   =========================== */

.nav-dropdown {
  position: relative;
}

.dropdown-menu {
  position: absolute;
  top: calc(100% + var(--space-2));
  left: 50%;
  transform: translateX(-50%);
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  padding: var(--space-4);
  min-width: 280px;
  opacity: 0;
  visibility: hidden;
  transform: translateX(-50%) translateY(-8px);
  transition: all var(--transition-base);
  z-index: var(--z-dropdown);
}

.dropdown-menu.active {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

.dropdown-content {
  display: flex;
  gap: var(--space-8);
}

#convertMenu .dropdown-content {
  min-width: 500px;
}

.dropdown-section {
  flex: 1;
  min-width: 0;
}

.dropdown-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  margin-bottom: var(--space-3);
}

.dropdown-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-3);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: all var(--transition-fast);
  margin-bottom: var(--space-1);
}

.dropdown-item:hover {
  background: var(--bg-secondary);
}

.item-icon {
  font-size: 1.5rem;
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.dropdown-item:hover .item-icon {
  background: var(--brand-100);
  transform: scale(1.1);
}

.item-name {
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.item-desc {
  font-size: 0.75rem;
  color: var(--text-tertiary);
}

/* ===========================
   Right Actions
   =========================== */

.nav-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

/* Theme Toggle */
.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background: var(--bg-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
  position: relative;
}

.theme-toggle:hover {
  background: var(--bg-secondary);
  border-color: var(--brand-600);
}

.theme-icon {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  transition: all var(--transition-base);
}

.sun-icon {
  opacity: 1;
}

.moon-icon {
  opacity: 0;
}

[data-theme="dark"] .sun-icon {
  opacity: 0;
}

[data-theme="dark"] .moon-icon {
  opacity: 1;
}

/* Sidebar Menu Toggle (in header) */
.sidebar-menu-toggle {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background: var(--bg-primary);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  cursor: pointer;
  transition: all var(--transition-fast);
  padding: 0;
}

.sidebar-menu-toggle:hover {
  background: var(--bg-secondary);
  border-color: var(--brand-600);
}

.sidebar-menu-toggle span {
  width: 20px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all var(--transition-fast);
}

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

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

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

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background: var(--bg-primary);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  cursor: pointer;
  transition: all var(--transition-fast);
  padding: 0;
}

.mobile-menu-toggle:hover {
  background: var(--bg-secondary);
  border-color: var(--brand-600);
}

.mobile-menu-toggle span {
  width: 20px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all var(--transition-fast);
}

.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
   =========================== */

.mobile-menu {
  display: none;
  padding: var(--space-6) 0;
  background: var(--bg-primary);
  border-top: 1px solid var(--border-color);
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-slow);
}

.mobile-menu.active {
  display: block;
  max-height: 600px;
}

.mobile-menu-section {
  margin-bottom: var(--space-6);
}

.mobile-menu-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  margin-bottom: var(--space-3);
  padding: 0 var(--space-4);
}

.mobile-menu-item {
  display: block;
  padding: var(--space-3) var(--space-4);
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-primary);
  text-decoration: none;
  transition: all var(--transition-fast);
  border-left: 3px solid transparent;
}

.mobile-menu-item:hover,
.mobile-menu-item:active {
  background: var(--bg-secondary);
  border-left-color: var(--brand-600);
  color: var(--brand-600);
}

/* ===========================
   Responsive Breakpoints
   =========================== */

@media (max-width: 768px) {
  .nav-container {
    padding: var(--space-3) 0;
  }

  .logo-icon {
    width: 36px;
    height: 36px;
  }

  .logo-name {
    font-size: 1.25rem;
  }

  .logo-tagline {
    font-size: 0.5625rem;
  }

  /* Hide desktop navigation on mobile */
  .nav-links {
    display: none;
  }
}

@media (min-width: 769px) {
  /* Hide mobile menu toggle on desktop */
  .mobile-menu-toggle {
    display: none;
  }

  .mobile-menu {
    display: none !important;
  }
}

/* ===========================
   Scroll Behavior
   =========================== */

@media (min-width: 769px) {
  .site-header {
    transition: padding var(--transition-base), box-shadow var(--transition-base);
  }

  .site-header.scrolled {
    padding: 0;
  }

  .site-header.scrolled .nav-container {
    padding: var(--space-2) 0;
  }

  .site-header.scrolled .logo-icon {
    width: 36px;
    height: 36px;
  }
}