:root {
  --ti-aurora-ink-9f3a: #0B1220;
  --ti-aurora-slate-2c8d: #111C2E;
  --ti-aurora-mist-7a1e: rgba(255,255,255,0.10);
  --ti-aurora-border-5d6b: rgba(255,255,255,0.16);
  --ti-aurora-cyan-4b2a: #2EE6D6;
  --ti-aurora-lime-8c11: #B7F34A;
  --ti-aurora-amber-1f77: #FFCC66;
  --ti-aurora-danger-6e2f: #FF5C7A;
  --ti-aurora-shadow-0c4e: 0 18px 50px rgba(0,0,0,0.35);
  --ti-font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --ti-font-mono: 'Courier New', Courier, monospace;
  --ti-spacing-xs: 0.5rem;
  --ti-spacing-sm: 1rem;
  --ti-spacing-md: 1.5rem;
  --ti-spacing-lg: 2.5rem;
  --ti-spacing-xl: 4rem;
  --ti-radius-sm: 8px;
  --ti-radius-md: 12px;
  --ti-radius-lg: 16px;
  --ti-transition-fast: 0.2s ease;
  --ti-transition-medium: 0.4s ease;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  font-family: var(--ti-font-sans);
  background: linear-gradient(135deg, var(--ti-aurora-ink-9f3a) 0%, var(--ti-aurora-slate-2c8d) 100%);
  color: rgba(255,255,255,0.92);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.skip-link {
  position: absolute;
  top: -100px;
  left: 0;
  background: var(--ti-aurora-cyan-4b2a);
  color: var(--ti-aurora-ink-9f3a);
  padding: var(--ti-spacing-sm) var(--ti-spacing-md);
  text-decoration: none;
  font-weight: 600;
  border-radius: 0 0 var(--ti-radius-sm) 0;
  z-index: 9999;
}

.skip-link:focus {
  top: 0;
  outline: 3px solid var(--ti-aurora-lime-8c11);
  outline-offset: 2px;
}

.site-header {
  background: var(--ti-aurora-mist-7a1e);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--ti-aurora-border-5d6b);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: var(--ti-aurora-shadow-0c4e);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--ti-spacing-md) var(--ti-spacing-lg);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--ti-spacing-sm);
}

.site-brand {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--ti-aurora-cyan-4b2a);
  letter-spacing: -0.02em;
  text-shadow: 0 2px 8px rgba(46,230,214,0.3);
}

.primary-nav {
  display: flex;
  gap: var(--ti-spacing-md);
  align-items: center;
}

.nav-link {
  color: rgba(255,255,255,0.8);
  text-decoration: none;
  font-weight: 500;
  padding: var(--ti-spacing-xs) var(--ti-spacing-sm);
  border-radius: var(--ti-radius-sm);
  transition: all var(--ti-transition-fast);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0;
  height: 2px;
  background: var(--ti-aurora-lime-8c11);
  transition: all var(--ti-transition-fast);
  transform: translateX(-50%);
}

.nav-link:hover {
  color: var(--ti-aurora-lime-8c11);
  background: rgba(183,243,74,0.1);
}

.nav-link:hover::after {
  width: 80%;
}

.nav-link.active {
  color: var(--ti-aurora-cyan-4b2a);
  background: rgba(46,230,214,0.15);
}

.nav-link:focus-visible {
  outline: 3px solid var(--ti-aurora-amber-1f77);
  outline-offset: 4px;
}

.breadcrumbs {
  max-width: 1200px;
  margin: var(--ti-spacing-md) auto 0;
  padding: 0 var(--ti-spacing-lg);
}

.breadcrumb-list {
  list-style: none;
  display: flex;
  gap: var(--ti-spacing-xs);
  align-items: center;
  font-size: 0.9rem;
  color: rgba(255,255,255,0.6);
}

.breadcrumb-list li {
  display: flex;
  align-items: center;
  gap: var(--ti-spacing-xs);
}

.breadcrumb-list li:not(:last-child)::after {
  content: '/';
  margin-left: var(--ti-spacing-xs);
  color: rgba(255,255,255,0.4);
}

.breadcrumb-list a {
  color: var(--ti-aurora-cyan-4b2a);
  text-decoration: none;
  transition: color var(--ti-transition-fast);
}

.breadcrumb-list a:hover {
  color: var(--ti-aurora-lime-8c11);
  text-decoration: underline;
}

.breadcrumb-list a:focus-visible {
  outline: 2px solid var(--ti-aurora-amber-1f77);
  outline-offset: 2px;
  border-radius: 3px;
}

.main-content {
  flex: 1;
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--ti-spacing-xl) var(--ti-spacing-lg);
  width: 100%;
}

.hero-section {
  text-align: center;
  margin-bottom: var(--ti-spacing-xl);
  padding: var(--ti-spacing-lg);
  background: linear-gradient(135deg, rgba(46,230,214,0.08) 0%, rgba(183,243,74,0.08) 100%);
  border-radius: var(--ti-radius-lg);
  border: 1px solid var(--ti-aurora-border-5d6b);
  box-shadow: var(--ti-aurora-shadow-0c4e);
}

.hero-title {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: var(--ti-spacing-md);
  background: linear-gradient(135deg, var(--ti-aurora-cyan-4b2a), var(--ti-aurora-lime-8c11));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
}

.hero-intro {
  font-size: 1.1rem;
  color: rgba(255,255,255,0.85);
  max-width: 900px;
  margin: 0 auto;
  line-height: 1.8;
}

.feature-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--ti-spacing-lg);
  margin-bottom: var(--ti-spacing-xl);
}

.feature-card {
  background: var(--ti-aurora-mist-7a1e);
  backdrop-filter: blur(10px);
  border: 1px solid var(--ti-aurora-border-5d6b);
  border-radius: var(--ti-radius-md);
  padding: var(--ti-spacing-lg);
  transition: all var(--ti-transition-medium);
  box-shadow: 0 4px 20px rgba(0,0,0,0.2);
}

.feature-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 12px 40px rgba(46,230,214,0.2);
  border-color: var(--ti-aurora-cyan-4b2a);
}

.feature-card h2 {
  font-size: 1.4rem;
  margin-bottom: var(--ti-spacing-sm);
  color: var(--ti-aurora-lime-8c11);
}

.feature-card p {
  color: rgba(255,255,255,0.8);
  margin-bottom: var(--ti-spacing-sm);
}

.authoritative-links {
  background: rgba(255,204,102,0.08);
  border-left: 4px solid var(--ti-aurora-amber-1f77);
  padding: var(--ti-spacing-lg);
  border-radius: var(--ti-radius-md);
  margin-bottom: var(--ti-spacing-xl);
}

.authoritative-links h2 {
  font-size: 1.6rem;
  margin-bottom: var(--ti-spacing-md);
  color: var(--ti-aurora-amber-1f77);
}

.authority-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--ti-spacing-sm);
}

.authority-list li {
  padding-left: var(--ti-spacing-md);
  position: relative;
}

.authority-list li::before {
  content: '→';
  position: absolute;
  left: 0;
  color: var(--ti-aurora-cyan-4b2a);
  font-weight: bold;
}

.authority-list a {
  color: var(--ti-aurora-cyan-4b2a);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: all var(--ti-transition-fast);
}

.authority-list a:hover {
  color: var(--ti-aurora-lime-8c11);
  border-bottom-color: var(--ti-aurora-lime-8c11);
}

.authority-list a:focus-visible {
  outline: 2px solid var(--ti-aurora-amber-1f77);
  outline-offset: 3px;
  border-radius: 3px;
}

.data-table-section {
  margin-bottom: var(--ti-spacing-xl);
}

.data-table-section h2 {
  font-size: 1.8rem;
  margin-bottom: var(--ti-spacing-md);
  color: var(--ti-aurora-lime-8c11);
}

table {
  width: 100%;
  border-collapse: collapse;
  background: var(--ti-aurora-mist-7a1e);
  backdrop-filter: blur(8px);
  border-radius: var(--ti-radius-md);
  overflow: hidden;
  box-shadow: 0 8px 30px rgba(0,0,0,0.3);
}

caption {
  caption-side: top;
  padding: var(--ti-spacing-sm);
  font-weight: 600;
  color: rgba(255,255,255,0.9);
  text-align: left;
  font-size: 0.95rem;
}

thead {
  background: linear-gradient(135deg, rgba(46,230,214,0.2), rgba(183,243,74,0.2));
}

th {
  padding: var(--ti-spacing-md);
  text-align: left;
  font-weight: 700;
  color: var(--ti-aurora-cyan-4b2a);
  border-bottom: 2px solid var(--ti-aurora-border-5d6b);
  font-size: 0.95rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

td {
  padding: var(--ti-spacing-md);
  border-bottom: 1px solid var(--ti-aurora-border-5d6b);
  color: rgba(255,255,255,0.85);
}

tbody tr {
  transition: background var(--ti-transition-fast);
}

tbody tr:hover {
  background: rgba(46,230,214,0.08);
}

tbody tr:last-child td {
  border-bottom: none;
}

.aqi-table .aqi-good {
  border-left: 4px solid #00E400;
}

.aqi-table .aqi-moderate {
  border-left: 4px solid #FFFF00;
}

.aqi-table .aqi-sensitive {
  border-left: 4px solid #FF7E00;
}

.aqi-table .aqi-unhealthy {
  border-left: 4px solid #FF0000;
}

.aqi-table .aqi-very-unhealthy {
  border-left: 4px solid #8F3F97;
}

.aqi-table .aqi-hazardous {
  border-left: 4px solid #7E0023;
}

.methodology-section {
  background: rgba(183,243,74,0.06);
  border-radius: var(--ti-radius-md);
  padding: var(--ti-spacing-lg);
  margin-bottom: var(--ti-spacing-xl);
  border: 1px solid var(--ti-aurora-border-5d6b);
}

.methodology-section h2 {
  font-size: 1.7rem;
  margin-bottom: var(--ti-spacing-md);
  color: var(--ti-aurora-lime-8c11);
}

.methodology-section p {
  color: rgba(255,255,255,0.8);
  margin-bottom: var(--ti-spacing-sm);
}

.internal-links-section {
  margin-bottom: var(--ti-spacing-xl);
}

.internal-links-section h2 {
  font-size: 1.8rem;
  margin-bottom: var(--ti-spacing-md);
  color: var(--ti-aurora-cyan-4b2a);
  text-align: center;
}

.cta-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--ti-spacing-lg);
}

.cta-card {
  background: linear-gradient(135deg, rgba(46,230,214,0.12), rgba(183,243,74,0.12));
  border: 2px solid var(--ti-aurora-border-5d6b);
  border-radius: var(--ti-radius-md);
  padding: var(--ti-spacing-lg);
  text-decoration: none;
  color: inherit;
  transition: all var(--ti-transition-medium);
  display: block;
}

.cta-card:hover {
  transform: scale(1.05);
  border-color: var(--ti-aurora-cyan-4b2a);
  box-shadow: 0 12px 40px rgba(46,230,214,0.25);
}

.cta-card:focus-visible {
  outline: 3px solid var(--ti-aurora-amber-1f77);
  outline-offset: 4px;
}

.cta-card h3 {
  font-size: 1.3rem;
  margin-bottom: var(--ti-spacing-sm);
  color: var(--ti-aurora-lime-8c11);
}

.cta-card p {
  color: rgba(255,255,255,0.75);
  line-height: 1.6;
}

.accessibility-note {
  background: rgba(255,92,122,0.1);
  border-left: 4px solid var(--ti-aurora-danger-6e2f);
  padding: var(--ti-spacing-lg);
  border-radius: var(--ti-radius-md);
  margin-bottom: var(--ti-spacing-xl);
}

.accessibility-note h2 {
  font-size: 1.5rem;
  margin-bottom: var(--ti-spacing-sm);
  color: var(--ti-aurora-danger-6e2f);
}

.accessibility-note p {
  color: rgba(255,255,255,0.8);
}

.faq-main {
  max-width: 900px;
}

.page-title {
  font-size: 2.2rem;
  margin-bottom: var(--ti-spacing-md);
  color: var(--ti-aurora-cyan-4b2a);
  text-align: center;
}

.page-intro {
  font-size: 1.05rem;
  color: rgba(255,255,255,0.8);
  margin-bottom: var(--ti-spacing-xl);
  text-align: center;
  line-height: 1.8;
}

.faq-accordion {
  display: flex;
  flex-direction: column;
  gap: var(--ti-spacing-md);
  margin-bottom: var(--ti-spacing-xl);
}

.faq-item {
  background: var(--ti-aurora-mist-7a1e);
  border: 1px solid var(--ti-aurora-border-5d6b);
  border-radius: var(--ti-radius-md);
  overflow: hidden;
  transition: all var(--ti-transition-fast);
}

.faq-item:hover {
  border-color: var(--ti-aurora-cyan-4b2a);
}

.faq-item[open] {
  border-color: var(--ti-aurora-lime-8c11);
  box-shadow: 0 8px 30px rgba(183,243,74,0.15);
}

.faq-item summary {
  padding: var(--ti-spacing-md);
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--ti-aurora-lime-8c11);
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: background var(--ti-transition-fast);
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: '+';
  font-size: 1.5rem;
  color: var(--ti-aurora-cyan-4b2a);
  transition: transform var(--ti-transition-fast);
}

.faq-item[open] summary::after {
  transform: rotate(45deg);
}

.faq-item summary:hover {
  background: rgba(183,243,74,0.08);
}

.faq-item summary:focus-visible {
  outline: 3px solid var(--ti-aurora-amber-1f77);
  outline-offset: -3px;
}

.faq-answer {
  padding: 0 var(--ti-spacing-md) var(--ti-spacing-md);
  color: rgba(255,255,255,0.85);
  line-height: 1.8;
}

.faq-answer p {
  margin-bottom: var(--ti-spacing-sm);
}

.about-main {
  max-width: 1000px;
}

.mission-section {
  background: linear-gradient(135deg, rgba(46,230,214,0.1), rgba(183,243,74,0.1));
  border-radius: var(--ti-radius-lg);
  padding: var(--ti-spacing-xl);
  margin-bottom: var(--ti-spacing-xl);
  border: 1px solid var(--ti-aurora-border-5d6b);
}

.mission-section h2 {
  font-size: 1.9rem;
  margin-bottom: var(--ti-spacing-md);
  color: var(--ti-aurora-cyan-4b2a);
}

.mission-section p {
  color: rgba(255,255,255,0.85);
  margin-bottom: var(--ti-spacing-md);
  line-height: 1.8;
}

.why-section,
.how-section,
.editorial-section,
.sources-section,
.contact-section,
.team-section {
  margin-bottom: var(--ti-spacing-xl);
}

.why-section h2,
.how-section h2,
.editorial-section h2,
.sources-section h2,
.contact-section h2,
.team-section h2 {
  font-size: 1.7rem;
  margin-bottom: var(--ti-spacing-md);
  color: var(--ti-aurora-lime-8c11);
}

.why-section p,
.how-section p,
.editorial-section p,
.sources-section p,
.contact-section p,
.team-section p {
  color: rgba(255,255,255,0.8);
  margin-bottom: var(--ti-spacing-md);
  line-height: 1.8;
}

.site-footer {
  background: var(--ti-aurora-slate-2c8d);
  border-top: 1px solid var(--ti-aurora-border-5d6b);
  padding: var(--ti-spacing-xl) var(--ti-spacing-lg);
  margin-top: auto;
}

.footer-nav {
  display: flex;
  justify-content: center;
  gap: var(--ti-spacing-lg);
  margin-bottom: var(--ti-spacing-md);
  flex-wrap: wrap;
}

.footer-link {
  color: rgba(255,255,255,0.7);
  text-decoration: none;
  transition: color var(--ti-transition-fast);
  font-weight: 500;
}

.footer-link:hover {
  color: var(--ti-aurora-cyan-4b2a);
}

.footer-link:focus-visible {
  outline: 2px solid var(--ti-aurora-amber-1f77);
  outline-offset: 3px;
  border-radius: 3px;
}

.contact-note {
  text-align: center;
  color: rgba(255,255,255,0.6);
  font-size: 0.9rem;
  margin-bottom: var(--ti-spacing-sm);
}

.copyright {
  text-align: center;
  color: rgba(255,255,255,0.5);
  font-size: 0.85rem;
}

@media (max-width: 768px) {
  .hero-title {
    font-size: 1.8rem;
  }
  .hero-intro {
    font-size: 1rem;
  }
  .header-container {
    flex-direction: column;
    align-items: flex-start;
  }
  .primary-nav {
    width: 100%;
    justify-content: space-around;
  }
  table {
    font-size: 0.85rem;
  }
  th,
  td {
    padding: var(--ti-spacing-xs);
  }
  .feature-cards {
    grid-template-columns: 1fr;
  }
  .cta-cards {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  :root {
    --ti-spacing-lg: 1.5rem;
    --ti-spacing-xl: 2.5rem;
  }
  .hero-title {
    font-size: 1.5rem;
  }
  .page-title {
    font-size: 1.7rem;
  }
  table {
    font-size: 0.75rem;
  }
}