/* ===== Sticky Header ===== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-light);
  z-index: var(--z-sticky);
  transition: all var(--transition-base);
}

[data-theme="dark"] .header {
  background: rgba(15, 23, 42, 0.92);
}

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

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--container-2xl);
  margin: 0 auto;
  padding: 0 var(--space-6);
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  flex-shrink: 0;
}

.logo-icon {
  width: 42px;
  height: 42px;
  background: var(--gradient-primary);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 800;
  font-size: 18px;
  font-family: var(--font-display);
  position: relative;
  overflow: hidden;
}

.logo-icon::after {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(45deg, transparent 30%, rgba(255,255,255,0.1) 50%, transparent 70%);
  animation: shimmer 3s infinite;
}

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

.logo-name {
  font-family: var(--font-display);
  font-size: var(--text-lg);
  font-weight: var(--font-extrabold);
  color: var(--text-primary);
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.logo-name span {
  color: var(--primary-500);
}

.logo-tagline {
  font-size: 10px;
  color: var(--text-tertiary);
  font-weight: var(--font-medium);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

/* Navigation */
.nav {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-link {
  position: relative;
  padding: 0.5rem 0.875rem;
  font-size: var(--text-sm);
  font-weight: var(--font-medium);
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.nav-link:hover {
  color: var(--primary-500);
  background: var(--primary-50);
}

[data-theme="dark"] .nav-link:hover {
  background: rgba(26, 115, 232, 0.1);
}

.nav-link.active {
  color: var(--primary-600);
  font-weight: var(--font-semibold);
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 50%;
  transform: translateX(-50%);
  width: 20px;
  height: 3px;
  background: var(--primary-500);
  border-radius: var(--radius-full);
}

/* Dropdown */
.nav-dropdown {
  position: relative;
}

.nav-dropdown-trigger {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-dropdown-trigger svg {
  width: 14px;
  height: 14px;
  transition: transform var(--transition-fast);
}

.nav-dropdown:hover .nav-dropdown-trigger svg {
  transform: rotate(180deg);
}

.nav-dropdown-menu {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%) translateY(8px);
  min-width: 240px;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  padding: var(--space-2);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-fast);
  z-index: var(--z-dropdown);
}

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

.nav-dropdown-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: 0.625rem 0.875rem;
  font-size: var(--text-sm);
  color: var(--text-secondary);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  text-decoration: none;
}

.nav-dropdown-item:hover {
  background: var(--primary-50);
  color: var(--primary-600);
}

[data-theme="dark"] .nav-dropdown-item:hover {
  background: rgba(26, 115, 232, 0.1);
}

.nav-dropdown-icon {
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  background: var(--bg-tertiary);
  font-size: 16px;
  flex-shrink: 0;
}

.nav-dropdown-label {
  font-weight: var(--font-medium);
  color: var(--text-primary);
}

.nav-dropdown-desc {
  font-size: var(--text-xs);
  color: var(--text-tertiary);
}

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

.search-toggle {
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  cursor: pointer;
}

.search-toggle:hover {
  background: var(--bg-tertiary);
  color: var(--primary-500);
}

.theme-toggle {
  width: 38px;
  height: 38px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  cursor: pointer;
  border: none;
  background: none;
}

.theme-toggle:hover {
  background: var(--bg-tertiary);
  color: var(--gold-500);
}

.theme-toggle .sun-icon { display: none; }
.theme-toggle .moon-icon { display: block; }

[data-theme="dark"] .theme-toggle .sun-icon { display: block; }
[data-theme="dark"] .theme-toggle .moon-icon { display: none; }

/* Mobile Menu */
.mobile-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 28px;
  cursor: pointer;
  padding: 4px 0;
  background: none;
  border: none;
}

.mobile-toggle span {
  display: block;
  height: 2.5px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all var(--transition-base);
}

.mobile-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

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

.mobile-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* Search Overlay */
.search-overlay {
  position: fixed;
  inset: 0;
  background: var(--bg-overlay);
  z-index: var(--z-modal);
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 120px;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-base);
}

.search-overlay.active {
  opacity: 1;
  visibility: visible;
}

.search-box {
  width: 100%;
  max-width: 640px;
  background: var(--bg-card);
  border-radius: var(--radius-2xl);
  box-shadow: var(--shadow-2xl);
  padding: var(--space-6);
  transform: translateY(-20px);
  transition: transform var(--transition-base);
}

.search-overlay.active .search-box {
  transform: translateY(0);
}

.search-input-wrapper {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: 0.75rem 1rem;
  background: var(--bg-tertiary);
  border-radius: var(--radius-xl);
  border: 2px solid transparent;
  transition: border-color var(--transition-fast);
}

.search-input-wrapper:focus-within {
  border-color: var(--primary-500);
  background: var(--bg-primary);
}

.search-input-wrapper svg {
  width: 20px;
  height: 20px;
  color: var(--text-tertiary);
  flex-shrink: 0;
}

.search-input {
  flex: 1;
  border: none;
  background: transparent;
  font-size: var(--text-lg);
  color: var(--text-primary);
  outline: none;
}

.search-input::placeholder {
  color: var(--text-tertiary);
}

.search-hints {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-4);
}

.search-hint {
  padding: 0.375rem 0.875rem;
  font-size: var(--text-xs);
  background: var(--bg-tertiary);
  color: var(--text-secondary);
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.search-hint:hover {
  background: var(--primary-100);
  color: var(--primary-700);
}

/* Mobile Navigation */
@media (max-width: 1024px) {
  .nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    flex-direction: column;
    background: var(--bg-primary);
    padding: var(--space-6);
    gap: var(--space-1);
    overflow-y: auto;
    transform: translateX(100%);
    transition: transform var(--transition-base);
  }

  .nav.active {
    transform: translateX(0);
  }

  .mobile-toggle {
    display: flex;
  }

  .nav-link {
    width: 100%;
    padding: 0.875rem;
    font-size: var(--text-base);
  }

  .nav-dropdown-menu {
    position: static;
    transform: none;
    box-shadow: none;
    border: none;
    background: var(--bg-tertiary);
    border-radius: var(--radius-lg);
    margin-top: var(--space-2);
    opacity: 1;
    visibility: visible;
    max-height: 0;
    overflow: hidden;
    padding: 0;
    transition: all var(--transition-base);
  }

  .nav-dropdown.open .nav-dropdown-menu {
    max-height: 500px;
    padding: var(--space-2);
  }

  .header-actions .btn {
    display: none;
  }
}