/* ==========================================================================
   SCPL Header & Navigation Styles
   ========================================================================== */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 84px;
  z-index: var(--z-header);
  background-color: transparent;
  transition: background-color var(--transition-normal), height var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
  border-bottom: 1px solid transparent;
}

.site-header.is-scrolled {
  background-color: var(--color-surface-glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  height: 72px;
  border-bottom-color: var(--color-border);
  box-shadow: var(--shadow-sm);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

/* Brand Logo */
.site-logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  z-index: 10;
}

.logo-symbol {
  width: 38px;
  height: 38px;
  flex-shrink: 0;
}

.site-logo-img {
  height: 48px;
  width: 48px;
  object-fit: contain;
  border-radius: var(--radius-xs);
  background-color: #FFFFFF;
  padding: 2px;
  border: 1px solid var(--color-border-subtle);
  flex-shrink: 0;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.site-logo:hover .site-logo-img {
  transform: scale(1.02);
  box-shadow: 0 2px 10px rgba(40, 78, 157, 0.15);
}

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

.logo-title {
  font-family: var(--font-primary);
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  color: var(--color-text-primary);
  line-height: 1;
}

.logo-title span {
  color: var(--color-accent);
}

.logo-tagline {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--color-text-secondary);
  line-height: 1;
  margin-top: 3px;
}

/* Desktop Navigation */
.desktop-nav {
  display: flex;
  align-items: center;
  gap: var(--space-8);
}

.nav-list {
  display: flex;
  align-items: center;
  gap: var(--space-6);
}

.nav-item {
  position: relative;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  padding: var(--space-2) 0;
  transition: color var(--transition-fast);
  position: relative;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-text-primary);
}

.nav-link::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0%;
  height: 2px;
  background-color: var(--color-accent);
  transition: width var(--transition-normal);
}

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

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

.nav-item:hover .nav-link .dropdown-caret {
  transform: rotate(180deg);
}

/* Dropdown Menu */
.nav-dropdown {
  position: absolute;
  top: 100%;
  left: -20px;
  min-width: 320px;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-3);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity var(--transition-normal), transform var(--transition-normal), visibility var(--transition-normal);
  pointer-events: none;
  z-index: var(--z-dropdown);
}

.nav-item:hover .nav-dropdown,
.nav-item:focus-within .nav-dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateY(4px);
  pointer-events: auto;
}

.dropdown-link {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-3);
  border-radius: var(--radius-sm);
  transition: background-color var(--transition-fast);
}

.dropdown-link:hover {
  background-color: var(--color-surface-light);
}

.dropdown-link-icon {
  width: 20px;
  height: 20px;
  margin-top: 2px;
  color: var(--color-accent);
  flex-shrink: 0;
}

.dropdown-link-text {
  display: flex;
  flex-direction: column;
}

.dropdown-link-title {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text-primary);
  line-height: var(--leading-tight);
}

.dropdown-link-desc {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-top: 2px;
  line-height: var(--leading-normal);
}

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

.btn-header-cta {
  padding: 0.65rem 1.35rem;
  font-size: var(--text-sm);
}

/* Theme Toggle Button */
.theme-toggle-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  border-radius: var(--radius-sm);
  background-color: var(--color-surface-light);
  border: 1px solid var(--color-border);
  color: var(--color-text-primary);
  cursor: pointer;
  transition: border-color var(--transition-fast), background-color var(--transition-fast), color var(--transition-fast);
  position: relative;
}

.theme-toggle-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background-color: var(--color-surface-elevated);
}

.theme-icon {
  width: 18px;
  height: 18px;
}

/* By default (White Mode): show moon icon (to switch to dark mode), hide sun */
.theme-toggle-btn .icon-sun {
  display: none;
}
.theme-toggle-btn .icon-moon {
  display: block;
}

/* When in Dark Mode: show sun icon (to switch back to light mode), hide moon */
[data-theme="dark"] .theme-toggle-btn .icon-sun {
  display: block;
}
[data-theme="dark"] .theme-toggle-btn .icon-moon {
  display: none;
}

/* Mobile Hamburger Button */
.mobile-menu-btn {
  display: none;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  background: var(--color-surface-light);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  color: var(--color-text-primary);
  cursor: pointer;
  z-index: calc(var(--z-header) + 10);
  transition: border-color var(--transition-fast);
}

.mobile-menu-btn:hover {
  border-color: var(--color-accent);
}

.hamburger-box {
  width: 20px;
  height: 14px;
  position: relative;
}

.hamburger-line {
  position: absolute;
  width: 100%;
  height: 2px;
  background-color: var(--color-text-primary);
  border-radius: 2px;
  transition: transform var(--transition-normal), opacity var(--transition-fast), top var(--transition-normal);
}

.hamburger-line:nth-child(1) { top: 0; }
.hamburger-line:nth-child(2) { top: 6px; }
.hamburger-line:nth-child(3) { top: 12px; }

/* Hamburger Open State */
.mobile-menu-btn[aria-expanded="true"] .hamburger-line:nth-child(1) {
  top: 6px;
  transform: rotate(45deg);
}

.mobile-menu-btn[aria-expanded="true"] .hamburger-line:nth-child(2) {
  opacity: 0;
}

.mobile-menu-btn[aria-expanded="true"] .hamburger-line:nth-child(3) {
  top: 6px;
  transform: rotate(-45deg);
}

/* Mobile Navigation Drawer */
.mobile-drawer {
  position: fixed;
  top: 0;
  right: 0;
  width: 100%;
  max-width: 400px;
  height: 100vh;
  background-color: var(--color-surface);
  border-left: 1px solid var(--color-border);
  padding: 100px var(--space-8) var(--space-8);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  transform: translateX(100%);
  transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  z-index: var(--z-header);
  box-shadow: var(--shadow-lg);
  overflow-y: auto;
}

.mobile-drawer.is-open {
  transform: translateX(0);
}

.mobile-drawer-overlay {
  position: fixed;
  inset: 0;
  background-color: var(--color-modal-backdrop);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-normal), visibility var(--transition-normal);
  z-index: calc(var(--z-header) - 1);
}

.mobile-drawer-overlay.is-active {
  opacity: 1;
  visibility: visible;
}

.mobile-nav-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.mobile-nav-link {
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-text-secondary);
  display: block;
  padding: var(--space-2) 0;
  border-bottom: 1px solid var(--color-border-subtle);
  transition: color var(--transition-fast);
}

.mobile-nav-link:hover,
.mobile-nav-link.active {
  color: var(--color-text-primary);
  padding-left: var(--space-2);
  border-bottom-color: var(--color-accent);
}

.mobile-nav-subitems {
  padding-left: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  margin-top: var(--space-2);
  margin-bottom: var(--space-2);
}

.mobile-nav-sublink {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  display: block;
  padding: var(--space-1) 0;
  transition: color var(--transition-fast);
}

.mobile-nav-sublink:hover,
.mobile-nav-sublink.active {
  color: var(--color-accent);
}

.mobile-drawer-footer {
  margin-top: var(--space-8);
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}