/* ============================================
   Site Header — Navigation Bar
   ============================================ */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: rgba(6, 9, 15, 0.96);
  border-bottom: 1px solid var(--color-border-light);
  transform: translateZ(0);
  -webkit-transform: translateZ(0);
  z-index: 1000;
}

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

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  color: var(--color-text-primary);
  text-decoration: none;
  font-weight: 700;
  font-size: var(--text-lg);
  letter-spacing: -0.02em;
}

.logo:hover {
  color: var(--color-text-primary);
}

.logo-icon {
  display: flex;
  align-items: center;
  line-height: 0;
}

.logo-icon svg {
  display: block;
}

.logo-icon img {
  width: 40px;
  height: 40px;
  display: block;
  object-fit: contain;
  border-radius: 5px;
}

.logo-text {
  color: var(--color-text-primary);
  font-weight: 700;
}

.logo-text-plain {
  font-weight: 400;
  color: var(--color-text-secondary);
  background: none;
  -webkit-text-fill-color: initial;
}

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

.nav-link {
  padding: var(--space-2) var(--space-3);
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
  font-weight: 500;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  white-space: nowrap;
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-link:hover {
  color: var(--color-text-primary);
  background: var(--color-surface);
}

.nav-link.active {
  color: var(--color-accent-light);
  background: var(--color-accent-glow);
}

.external-icon {
  opacity: 0.5;
  width: 14px;
  height: 14px;
}

.lang-switch {
  padding: var(--space-2) var(--space-4);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  font-size: var(--text-xs);
  font-weight: 600;
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition-fast);
  white-space: nowrap;
  margin-left: var(--space-2);
}

.lang-switch:hover {
  color: var(--color-accent-light);
  border-color: var(--color-accent);
  background: var(--color-accent-glow);
}

.theme-toggle {
  padding: var(--space-2) var(--space-2);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  font-size: var(--text-sm);
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all var(--transition-fast);
  line-height: 1;
  margin-left: var(--space-1);
}

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

.mobile-menu-btn {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-2);
}

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

@media (max-width: 768px) {
  .mobile-menu-btn {
    display: flex;
  }

  .nav-links {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    height: calc(100vh - var(--header-height));
    flex-direction: column;
    justify-content: flex-start;
    align-items: stretch;
    background: rgba(15, 15, 24, 0.98);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    padding: var(--space-4) var(--space-4) 0;
    gap: 0;
    transform: translateX(100%);
    transition: transform var(--transition-normal);
    z-index: 999;
    overflow-y: auto !important;
    -webkit-overflow-scrolling: touch;
  }

  .nav-links.open {
    transform: translateX(0);
  }

  .nav-link {
    font-size: var(--text-base);
    padding: var(--space-3) var(--space-4);
    width: 100%;
    justify-content: flex-start;
    border-radius: var(--radius-md);
  }

  .nav-link:active {
    background: var(--color-surface);
  }

  .nav-dropdown-btn {
    font-size: var(--text-base);
    padding: var(--space-3) var(--space-4);
    width: 100%;
    justify-content: flex-start;
  }

  .nav-dropdown-menu {
    position: static !important;
    box-shadow: none;
    border: none;
    background: transparent;
    margin-top: 0;
    animation: none;
    min-width: auto;
  }

  .lang-switch {
    margin-left: 0;
    margin-top: var(--space-2);
    align-self: center;
  }

  .theme-toggle {
    margin-top: var(--space-2);
    align-self: center;
  }
}

/* ============================================
   Site Footer
   ============================================ */

.site-footer {
  background: rgba(6,9,15,0.60);
  backdrop-filter: blur(12px) saturate(120%);
  -webkit-backdrop-filter: blur(12px) saturate(120%);
  border-top: 1px solid var(--color-border-light);
  padding: var(--space-4) 0;
  transform: translateZ(0);
  -webkit-transform: translateZ(0);
}

.footer-inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 var(--space-6);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  flex-wrap: wrap;
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.footer-inner a {
  color: var(--color-text-muted);
  transition: color var(--transition-fast);
}

.footer-inner a:hover {
  color: var(--color-accent-light);
}

.footer-sep {
  display: inline-block;
  width: 1px;
  height: 14px;
  background: var(--color-border);
  margin: 0 var(--space-1);
}

.footer-icp-icon {
  width: 16px;
  height: 16px;
  vertical-align: middle;
}

/* ============================================
   Nav Dropdown (GitHub projects)
   ============================================ */
.nav-dropdown {
  position: relative;
}

.nav-dropdown-btn {
  padding: var(--space-2) var(--space-3);
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
  font-weight: 500;
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  background: none;
  border: none;
  cursor: pointer;
  font-family: inherit;
}

.nav-dropdown-btn:hover {
  color: var(--color-text-primary);
  background: var(--color-surface);
}

.dropdown-arrow {
  transition: transform var(--transition-fast);
}

.dropdown-arrow.open {
  transform: rotate(180deg);
}

.nav-dropdown-menu {
  position: absolute;
  top: 100%;
  right: 0;
  margin-top: var(--space-2);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  min-width: 200px;
  padding: var(--space-2);
  z-index: 1100;
  animation: fadeInScale 0.15s ease forwards;
}

.nav-dropdown-item {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  width: 100%;
  text-align: left;
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-md);
  text-decoration: none;
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  transition: all var(--transition-fast);
  background: none;
  border: none;
  cursor: pointer;
  font-family: inherit;
}

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

.nav-dropdown-overlay {
  position: fixed;
  inset: 0;
  z-index: 1099;
}

.dropdown-item-title {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text-primary);
}

.dropdown-item-desc {
  display: block;
  width: 100%;
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  margin-top: 1px;
}

.nav-dropdown-divider {
  height: 1px;
  background: var(--color-border-light);
  margin: var(--space-1) 0;
}