/* nav.css — Header, nav, breadcrumbs, mobile menu */

/* ===== SITE HEADER ===== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--header-height);
  background: var(--color-header-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: none;
  z-index: 1000;
  transition: box-shadow var(--transition-base);
}

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

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--sp-4);
}

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  font-family: 'IBM Plex Sans', sans-serif;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-text);
  text-decoration: none !important;
  flex-shrink: 0;
}

.logo img {
  width: 72px;
  height: 72px;
}

/* Main nav */
.nav-list {
  display: flex;
  gap: var(--sp-1);
}

.nav-link {
  display: flex;
  align-items: center;
  padding: var(--sp-2) var(--sp-2);
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none !important;
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.nav-link:hover {
  color: var(--color-text);
  background: rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] .nav-link:hover {
  background: rgba(255, 255, 255, 0.15);
}

.nav-link.active,
.nav-link[aria-current="page"] {
  color: var(--color-accent);
  font-weight: 600;
}

/* Header actions */
.header-actions {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
}

/* Theme toggle button */
.theme-toggle-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-md);
  color: var(--color-text-muted);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.theme-toggle-btn:hover {
  color: var(--color-text);
  background: rgba(0, 0, 0, 0.04);
}

[data-theme="dark"] .theme-toggle-btn:hover {
  background: rgba(255, 255, 255, 0.06);
}

/* Show/hide sun/moon/system icons based on data-mode attribute.
   data-mode is set by theme.js on the toggle button:
   dark = moon, light = sun, system = monitor */
.icon-sun,
.icon-moon,
.icon-system { display: none; }

[data-mode="dark"] .icon-moon { display: block; }
[data-mode="light"] .icon-sun { display: block; }
[data-mode="system"] .icon-system { display: block; }

/* ===== SEARCH ===== */
.search-container {
  position: relative;
}

.search-input {
  width: 180px;
  padding: var(--sp-2) var(--sp-3);
  padding-left: 36px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-full);
  font-size: 0.85rem;
  color: var(--color-text);
  transition: width var(--transition-base), border-color var(--transition-fast);
}

.search-input:focus {
  width: 240px;
  border-color: var(--color-accent);
  outline: none;
}

.search-icon {
  position: absolute;
  left: 10px;
  top: 50%;
  transform: translateY(-50%);
  width: 16px;
  height: 16px;
  color: var(--color-text-muted);
  pointer-events: none;
}

.search-results {
  position: absolute;
  top: calc(100% + var(--sp-2));
  right: 0;
  width: 360px;
  max-height: 400px;
  overflow-y: auto;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-hover);
  z-index: 100;
}

.search-result {
  display: block;
  padding: var(--sp-3) var(--sp-4);
  text-decoration: none;
  color: var(--color-text);
  border-bottom: 1px solid var(--color-border-light);
  transition: background-color var(--transition-fast);
}

.search-result:last-child {
  border-bottom: none;
}

.search-result:hover, .search-result:focus {
  background: rgba(0, 0, 0, 0.03);
}

[data-theme="dark"] .search-result:hover,
[data-theme="dark"] .search-result:focus {
  background: rgba(255, 255, 255, 0.04);
}

.search-result-title {
  display: block;
  font-weight: 500;
  font-size: 0.9rem;
}

.search-result-section {
  display: block;
  font-size: 0.75rem;
  color: var(--color-text-muted);
  margin-top: 2px;
}

.search-empty {
  padding: var(--sp-6);
  text-align: center;
  color: var(--color-text-muted);
  font-size: 0.9rem;
}

/* ===== MOBILE MENU ===== */
.mobile-menu-btn {
  display: none;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  color: var(--color-text);
}

.mobile-menu-btn svg {
  width: 24px;
  height: 24px;
}

.mobile-nav {
  display: none;
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: var(--sp-4);
  z-index: 999;
  box-shadow: var(--shadow-hover);
}

.mobile-nav.open {
  display: block;
}

.mobile-nav .nav-link {
  display: block;
  padding: var(--sp-3) var(--sp-4);
  font-size: 1rem;
}

@media (max-width: 768px) {
  .nav-list {
    display: none;
  }
  .search-input {
    width: 140px;
  }
  .search-input:focus {
    width: 180px;
  }
  .search-results {
    width: 280px;
  }
  .mobile-menu-btn {
    display: flex;
  }
}

@media (max-width: 480px) {
  .search-container {
    display: none;
  }
  .mobile-nav .search-container-mobile {
    display: block;
    margin-bottom: var(--sp-4);
  }
  .mobile-nav .search-container-mobile .search-input {
    width: 100%;
  }
}

/* ===== BREADCRUMB ===== */
.breadcrumb {
  padding: var(--sp-3) 0;
  margin-top: var(--header-height);
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--sp-1);
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--sp-4);
}

.breadcrumb li {
  display: flex;
  align-items: center;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

.breadcrumb li:not(:last-child)::after {
  content: '/';
  margin-left: var(--sp-2);
  color: var(--color-border);
}

.breadcrumb a {
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}

.breadcrumb a:hover {
  color: var(--color-accent);
}

.breadcrumb [aria-current="page"] {
  color: var(--color-text);
  font-weight: 500;
}

/* ===== SKIP LINK ===== */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 10000;
  padding: var(--sp-2) var(--sp-4);
  background: var(--color-accent);
  color: #fff;
  font-weight: 600;
  border-radius: 0 0 var(--radius-md) 0;
  text-decoration: none;
}

.skip-link:focus {
  left: 0;
}

/* ===== FOCUS VISIBLE ===== */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

button:focus-visible,
a:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}