/* --- Layout Grid Container --- */
.container {
  width: 100%;
  max-width: 1240px;
  margin-left: auto;
  margin-right: auto;
  padding-left: 1.5rem;
  padding-right: 1.5rem;
}

@media (max-width: 768px) {
  .container {
    padding-left: 1.125rem;
    padding-right: 1.125rem;
  }
}

@media (max-width: 480px) {
  .container {
    padding-left: 0.875rem;
    padding-right: 0.875rem;
  }
}

.section-spacer {
  padding-top: 5rem;
  padding-bottom: 5rem;
}

@media (max-width: 768px) {
  .section-spacer {
    padding-top: 3.5rem;
    padding-bottom: 3.5rem;
  }
  .card {
    padding: 1.25rem;
    border-radius: var(--radius-lg);
  }
}

/* --- Subpage Hero --- */
.page-hero {
  padding: 4rem 0 3rem;
  text-align: center;
  background: radial-gradient(circle at 50% 10%, rgba(0, 98, 255, 0.08) 0%, transparent 60%);
  border-bottom: 1px solid var(--border-subtle);
}

@media (max-width: 768px) {
  .page-hero {
    padding: 2.75rem 0 2rem;
  }
}

/* --- Global Site Header & Navigation --- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  width: 100%;
  background: var(--bg-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  transition: background var(--transition-normal), border-color var(--transition-normal);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  width: 100%;
  max-width: 100%;
  padding-left: clamp(1.25rem, 3.5vw, 3.5rem);
  padding-right: clamp(1.25rem, 3.5vw, 3.5rem);
  box-sizing: border-box;
  gap: 1rem;
}

.brand-logo {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  flex-shrink: 0;
  transition: opacity var(--transition-fast), transform var(--transition-fast);
}

.brand-logo:hover {
  opacity: 0.9;
}

.gnb-nav {
  display: flex;
  align-items: center;
  gap: clamp(0.75rem, 1.4vw, 1.75rem);
  list-style: none;
  margin: 0;
  padding: 0;
  flex-wrap: nowrap;
}

.gnb-link {
  font-size: clamp(0.875rem, 0.95vw, 0.9375rem);
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  position: relative;
  padding: 0.5rem 0.35rem;
  white-space: nowrap;
  transition: color var(--transition-fast);
}

.gnb-link:hover,
.gnb-link.active {
  color: var(--color-ai-electric);
}

.gnb-link.active::after {
  content: "";
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--color-ai-electric);
  border-radius: var(--radius-full);
}

/* GNB Dropdown Menu */
.gnb-item {
  position: relative;
  display: flex;
  align-items: center;
}

.gnb-dropdown {
  position: absolute;
  top: calc(100% + 4px);
  left: 50%;
  transform: translateX(-50%) translateY(4px);
  min-width: 210px;
  background: var(--dropdown-bg, var(--bg-surface-primary));
  border: 1px solid var(--dropdown-border, var(--border-strong));
  border-radius: var(--radius-md);
  padding: 0.5rem;
  box-shadow: var(--dropdown-shadow, var(--shadow-xl));
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: opacity var(--transition-fast), transform var(--transition-fast), visibility var(--transition-fast);
  z-index: 1050;
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

/* Invisible hover bridge to prevent menu from closing when moving mouse */
.gnb-dropdown::before {
  content: "";
  position: absolute;
  top: -12px;
  left: 0;
  width: 100%;
  height: 12px;
}

.gnb-item:hover .gnb-dropdown,
.gnb-item:focus-within .gnb-dropdown {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0);
}

/* Align dropdown inside viewport for first and last items */
.gnb-item:first-child .gnb-dropdown {
  left: 0;
  transform: translateY(4px);
}

.gnb-item:first-child:hover .gnb-dropdown,
.gnb-item:first-child:focus-within .gnb-dropdown {
  transform: translateY(0);
}

.gnb-item:nth-last-child(-n+2) .gnb-dropdown {
  left: auto;
  right: 0;
  transform: translateY(4px);
}

.gnb-item:nth-last-child(-n+2):hover .gnb-dropdown,
.gnb-item:nth-last-child(-n+2):focus-within .gnb-dropdown {
  transform: translateY(0);
}

.gnb-dropdown-link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.6rem 0.85rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-primary);
  text-decoration: none;
  white-space: nowrap;
  transition: background var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
}

.gnb-dropdown-link .dropdown-dot {
  color: var(--color-ai-electric);
  font-weight: 700;
  font-size: 1.1rem;
  line-height: 1;
}

.gnb-dropdown-link:hover {
  color: var(--color-ai-electric);
  background: var(--bg-surface-secondary);
  transform: translateX(3px);
}

/* Mobile Accordion Submenu */
.drawer-sublist {
  list-style: none;
  padding-left: 1rem;
  margin: 0.35rem 0 0.65rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  border-left: 2px solid var(--border-subtle);
}

.drawer-sublink {
  font-size: 0.875rem;
  color: var(--text-muted);
  text-decoration: none;
  padding: 0.35rem 0.5rem;
  display: block;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast);
}

.drawer-sublink:hover {
  color: var(--color-ai-electric);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-shrink: 0;
}

.theme-toggle-btn {
  position: relative;
  overflow: hidden;
  background: var(--bg-surface-secondary);
  border: 1px solid var(--border-subtle);
  width: 38px;
  height: 38px;
  border-radius: var(--radius-full);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--text-primary);
  transition: border-color var(--transition-fast), transform var(--transition-fast), box-shadow var(--transition-fast), background-color var(--transition-base);
  padding: 0;
  outline: none;
}

.theme-toggle-btn:hover {
  border-color: var(--color-ai-electric);
  transform: translateY(-1px) scale(1.05);
  box-shadow: 0 0 16px rgba(0, 98, 255, 0.25);
}

.theme-toggle-btn:focus-visible {
  outline: 2px solid var(--color-ai-electric);
  outline-offset: 2px;
}

.theme-icon {
  position: absolute;
  top: 50%;
  left: 50%;
  width: 19px;
  height: 19px;
  margin-top: -9.5px;
  margin-left: -9.5px;
  display: block;
  pointer-events: none;
  transition: transform 0.45s cubic-bezier(0.34, 1.56, 0.64, 1), opacity 0.25s ease, color 0.25s ease;
}

/* Dark Mode: Sun icon active (warm amber), Moon rotates out */
[data-theme="dark"] .theme-icon-sun {
  opacity: 1;
  transform: rotate(0deg) scale(1);
  color: #FBBF24;
}

[data-theme="dark"] .theme-icon-moon {
  opacity: 0;
  transform: rotate(-90deg) scale(0.4);
  color: var(--text-muted);
}

/* Light Mode: Moon icon active (cobalt blue), Sun rotates out */
[data-theme="light"] .theme-icon-sun {
  opacity: 0;
  transform: rotate(90deg) scale(0.4);
  color: var(--text-muted);
}

[data-theme="light"] .theme-icon-moon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
  color: var(--color-ai-electric);
}

.mobile-menu-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.4rem;
  color: var(--text-primary);
  border-radius: var(--radius-sm);
  align-items: center;
  justify-content: center;
}

/* Mobile Drawer Navigation */
.drawer-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.65);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  z-index: 1050;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-normal);
}

.drawer-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.mobile-drawer {
  position: fixed;
  top: 0;
  right: -360px;
  width: 320px;
  max-width: 85vw;
  height: 100vh;
  background: var(--dropdown-bg, var(--bg-surface-primary));
  border-left: 1px solid var(--border-subtle);
  z-index: 1100;
  padding: 1.75rem;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow-xl);
  transition: right 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

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

.drawer-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid var(--border-subtle);
  padding-bottom: 1.25rem;
  margin-bottom: 1.5rem;
}

.drawer-title {
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--text-primary);
}

.drawer-close-btn {
  background: none;
  border: none;
  font-size: 1.75rem;
  line-height: 1;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 0.25rem;
  transition: color var(--transition-fast);
}

.drawer-close-btn:hover {
  color: var(--text-primary);
}

.drawer-menu {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  margin: 0;
  padding: 0;
}

.drawer-link {
  display: block;
  padding: 0.65rem 0.5rem;
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  text-decoration: none;
  transition: background var(--transition-fast), color var(--transition-fast);
}

.drawer-link:hover,
.drawer-link.active {
  color: var(--color-ai-electric);
  background: var(--bg-surface-secondary);
}

@media (max-width: 992px) {
  .gnb-nav {
    display: none !important;
  }
  .mobile-menu-btn {
    display: inline-flex !important;
  }
}

@media (max-width: 480px) {
  .header-inner {
    height: 64px;
    padding-left: 1rem;
    padding-right: 1rem;
  }
  .btn-lg {
    padding: 0.8rem 1.25rem;
    font-size: 0.95rem;
  }
}

/* --- Global Site Footer --- */
.site-footer {
  background: var(--bg-surface-secondary);
  border-top: 1px solid var(--border-subtle);
  padding: 4.5rem 0 3rem;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 3.5rem;
}

.footer-heading {
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 1rem;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
  margin: 0;
  padding: 0;
}

.footer-links a {
  color: var(--text-secondary);
  transition: color var(--transition-fast);
}

.footer-links a:hover {
  color: var(--color-ai-electric);
}

.footer-bottom {
  border-top: 1px solid var(--border-subtle);
  padding-top: 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.8125rem;
  color: var(--text-muted);
}

@media (max-width: 992px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 2.5rem;
  }
}

@media (max-width: 768px) {
  .site-footer {
    padding: 3rem 0 2rem;
  }
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
    margin-bottom: 2.5rem;
  }
  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.75rem;
  }
}