:root {
  --background: #ffffff;
  --text: #1a1a1a;
  --accent: #111111;
  --accent-alt: #5a5a5a;
  --border: #e6e6e6;
  --shadow: 0 8px 20px rgba(0, 0, 0, 0.06);
  --transition: 0.3s ease;
}

[data-theme="dark"] {
  --background: #111111;
  --text: #e5e5e5;
  --accent: #f5f5f5;
  --accent-alt: #9e9e9e;
  --border: #2a2a2a;
  --shadow: 0 8px 20px rgba(0, 0, 0, 0.5);
}

/* Accessibility utility: visually hidden but screen-reader accessible */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.header-shell {
  width: min(1100px, 100%);
  margin: 16px auto; /* center header and add vertical spacing */
  padding: 0 12px; /* prevent header from touching edges on small screens */
  position: relative; /* establish stacking context for header */
  z-index: 1000;
}

header.site-header {
  background: var(--background);
  border-radius: 18px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  padding: 16px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  position: relative;
  transition: transform var(--transition), box-shadow var(--transition);
  z-index: 2000; /* keep header above page content */
}

header.site-header:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 28px rgba(0, 0, 0, 0.08);
}

.brand {
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: 0.1em;
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  color: var(--text);
}

.brand:visited,
.brand:hover,
.brand:focus-visible {
  text-decoration: none;
  color: var(--text);
}

.search-wrapper {
  flex: 1;
  max-width: 420px;
  position: relative;
  z-index: 3000; /* ensure dropdown overlays header children */
}

.search-input {
  width: 100%;
  padding: 12px 16px 12px 44px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: #fafbff;
  font-size: 0.95rem;
  color: var(--text);
  transition: border-color var(--transition), box-shadow var(--transition), background var(--transition);
}

.search-input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(0, 0, 0, 0.12);
  background: #ffffff;
}

.search-icon {
  position: absolute;
  top: 50%;
  left: 16px;
  transform: translateY(-50%);
  pointer-events: none;
  color: #6c757d;
  display: inline-flex;
}

/* Search dropdown */
.search-panel {
  position: absolute;
  inset: calc(100% + 8px) 0 auto 0;
  background: var(--background);
  border: 1px solid var(--border);
  border-radius: 14px;
  box-shadow: var(--shadow);
  padding: 10px;
  display: none;
  z-index: 5000; /* above header and nav */
}

.search-panel[aria-hidden="false"] {
  display: block;
}

.search-filters {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 4px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 8px;
}

.search-advanced {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px 12px;
  padding: 8px 4px 10px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 8px;
}

.search-advanced .field { display: grid; gap: 6px; }
.search-advanced .field label { font-size: 0.85rem; color: rgba(34,34,34,0.72); }
.search-advanced select,
.search-advanced input[type="number"],
.search-advanced input[type="text"] {
  width: 100%;
  padding: 8px 10px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--background);
}

.search-advanced .field-range .range-inputs { display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; gap: 8px; }
.search-advanced .field-range .to { color: rgba(34,34,34,0.6); font-size: 0.9rem; }

.search-advanced .field-checkbox .checkbox { display: inline-flex; align-items: center; gap: 8px; }

.filter-chip {
  padding: 8px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--background);
  color: var(--text);
  font-size: 0.85rem;
  cursor: pointer;
}

.filter-chip.active {
  background: linear-gradient(135deg, var(--accent), var(--accent-alt));
  color: #fff;
  border-color: transparent;
}

.search-results {
  list-style: none;
  margin: 0;
  padding: 6px;
  display: grid;
  gap: 6px;
  max-height: 360px;
  overflow: auto;
}

.result-item {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 8px;
  align-items: center;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--background);
  cursor: pointer;
}

.result-item:hover,
.result-item:focus-visible {
  border-color: rgba(0, 0, 0, 0.22);
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.08);
}

.result-item.active {
  border-color: rgba(0, 0, 0, 0.22);
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.08);
}

.result-title { font-weight: 700; color: var(--text); }
.result-sub { font-size: 0.85rem; color: rgba(34,34,34,0.6); }
.result-tag { font-size: 0.75rem; opacity: 0.7; }

nav.primary-nav {
  display: flex;
  align-items: center;
  gap: 14px;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 18px;
  border-radius: 999px;
  border: 1px solid var(--border);
  transition: background var(--transition), color var(--transition), box-shadow var(--transition), border-color var(--transition), transform var(--transition);
  font-weight: 500;
  background: var(--background);
  text-decoration: none;
  color: var(--text);
}

.nav-link:visited {
  text-decoration: none;
  color: var(--text);
}

.nav-link:hover,
.nav-link:focus-visible {
  background: rgba(0, 0, 0, 0.06);
  color: var(--accent);
  border-color: rgba(0, 0, 0, 0.35);
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.12);
  text-decoration: none;
}

.nav-link.active {
  background: linear-gradient(135deg, var(--accent), var(--accent-alt));
  color: #ffffff;
  border-color: transparent;
  box-shadow: 0 8px 16px rgba(0, 0, 0, 0.2);
  font-weight: 600;
}

.nav-link.active:hover,
.nav-link.active:focus-visible {
  background: linear-gradient(135deg, var(--accent), var(--accent-alt));
  color: #ffffff;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.24);
  transform: translateY(-1px);
}

.menu-toggle {
  display: none;
  width: 42px;
  height: 42px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--background);
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
}

.menu-toggle span,
.menu-toggle span::before,
.menu-toggle span::after {
  display: block;
  width: 18px;
  height: 2px;
  background: var(--text);
  border-radius: 999px;
  transition: transform var(--transition), opacity var(--transition);
  position: relative;
}

.menu-toggle span::before,
.menu-toggle span::after {
  content: "";
  position: absolute;
  left: 0;
}

.menu-toggle span::before {
  transform: translateY(-6px);
}

.menu-toggle span::after {
  transform: translateY(6px);
}

.menu-toggle.active {
  border-color: transparent;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.16);
  transform: rotate(90deg);
}

.menu-toggle.active span {
  background: transparent;
}

.menu-toggle.active span::before {
  transform: rotate(45deg);
}

.menu-toggle.active span::after {
  transform: rotate(-45deg);
}

@media (max-width: 920px) {
  header.site-header {
    flex-wrap: wrap;
    gap: 14px 18px;
    padding: 16px 18px;
  }

  .search-wrapper {
    order: 3;
    flex: 1 1 100%;
    max-width: none;
  }

  .menu-toggle {
    display: inline-flex;
    order: 2;
  }

  nav.primary-nav {
    order: 4;
    width: 100%;
    flex-direction: column;
    align-items: stretch;
    gap: 8px;
    overflow: hidden;
    max-height: 0;
    opacity: 0;
    border-top: 1px solid transparent;
    transition: max-height var(--transition), opacity var(--transition), border-color var(--transition);
  }

  nav.primary-nav.open {
    padding-top: 12px;
    max-height: 320px;
    opacity: 1;
    border-color: var(--border);
  }

  .nav-link {
    display: flex;
    justify-content: center;
    padding: 12px 20px;
    border-radius: 14px;
  }
}