:root {
  --bg-main: #060b14;
  --bg-elevated: #0d1626;
  --bg-card: rgba(16, 26, 44, 0.78);
  --bg-card-hover: rgba(23, 37, 62, 0.92);
  --border-subtle: rgba(148, 163, 184, 0.14);
  --border-highlight: rgba(251, 146, 60, 0.45);
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-warm: #fb923c;
  --accent-hot: #ef4444;
  --accent-cool: #38bdf8;
  --accent-green: #10b981;
  --radius-lg: 20px;
  --radius-md: 14px;
  --radius-sm: 10px;
  --shadow-lg: 0 24px 48px -12px rgba(0, 0, 0, 0.6);
  --max-width: 1180px;
}

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

html {
  scroll-behavior: smooth;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: var(--bg-main);
  color: var(--text-primary);
  line-height: 1.6;
}

body {
  min-height: 100vh;
  background:
    radial-gradient(circle at 15% 10%, rgba(239, 68, 68, 0.12), transparent 38%),
    radial-gradient(circle at 85% 18%, rgba(56, 189, 248, 0.10), transparent 36%),
    radial-gradient(circle at 50% 85%, rgba(16, 185, 129, 0.08), transparent 42%),
    var(--bg-main);
  overflow-x: hidden;
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Navbar */
.navbar {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  background: rgba(6, 11, 20, 0.8);
  border-bottom: 1px solid var(--border-subtle);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4.5rem;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.02em;
}

.brand-dot {
  width: 12px;
  height: 12px;
  border-radius: 999px;
  background: linear-gradient(135deg, var(--accent-warm), var(--accent-hot));
  box-shadow: 0 0 14px rgba(251, 146, 60, 0.75);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
}

.nav-links a {
  font-size: 0.92rem;
  color: var(--text-secondary);
  transition: color 0.2s ease;
}

.nav-links a:hover {
  color: var(--text-primary);
}

.nav-cta {
  padding: 0.5rem 1rem;
  border-radius: 999px;
  background: rgba(251, 146, 60, 0.14);
  border: 1px solid rgba(251, 146, 60, 0.4);
  color: #fed7aa !important;
  font-weight: 600;
}

.nav-cta:hover {
  background: rgba(251, 146, 60, 0.24);
}

/* Hero */
.hero {
  padding: 5.5rem 0 4rem;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.4rem 0.9rem;
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  background: rgba(239, 68, 68, 0.12);
  border: 1px solid rgba(239, 68, 68, 0.35);
  color: #fca5a5;
  margin-bottom: 1.5rem;
}

.pulse-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent-hot);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0% {
    box-shadow: 0 0 0 0 rgba(239, 68, 68, 0.7);
  }
  70% {
    box-shadow: 0 0 0 8px rgba(239, 68, 68, 0);
  }
  100% {
    box-shadow: 0 0 0 0 rgba(239, 68, 68, 0);
  }
}

.hero h1 {
  font-size: clamp(2.4rem, 5vw, 4.1rem);
  line-height: 1.08;
  letter-spacing: -0.03em;
  max-width: 850px;
  margin-bottom: 1.4rem;
}

.gradient-text {
  background: linear-gradient(95deg, #fb923c 0%, #f87171 50%, #38bdf8 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-lead {
  font-size: clamp(1.06rem, 1.8vw, 1.25rem);
  color: var(--text-secondary);
  max-width: 720px;
  margin-bottom: 2.2rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 3.5rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.85rem 1.5rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.96rem;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.2s ease, background 0.2s ease;
  border: none;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-warm), var(--accent-hot));
  color: #fff;
  box-shadow: 0 12px 28px -8px rgba(239, 68, 68, 0.55);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
}

/* Warming Stripes Bar */
.stripes-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.4rem 1.5rem;
  margin-bottom: 2.5rem;
  box-shadow: var(--shadow-lg);
}

.stripes-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 0.75rem;
  font-size: 0.86rem;
  color: var(--text-secondary);
}

.warming-stripes {
  display: grid;
  grid-template-columns: repeat(36, 1fr);
  height: 44px;
  border-radius: var(--radius-sm);
  overflow: hidden;
  gap: 1px;
}

.stripe-bar {
  height: 100%;
  transition: transform 0.15s ease;
}

.stripe-bar:hover {
  transform: scaleY(1.12);
}

/* KPI Grid */
.kpi-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
}

.kpi-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.5rem;
  transition: border-color 0.2s ease, background 0.2s ease;
}

.kpi-card:hover {
  border-color: rgba(251, 146, 60, 0.35);
  background: var(--bg-card-hover);
}

.kpi-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

.kpi-value {
  font-size: 2.1rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 0.35rem;
}

.kpi-value.hot {
  color: var(--accent-warm);
}

.kpi-value.danger {
  color: #f87171;
}

.kpi-value.cool {
  color: var(--accent-cool);
}

.kpi-meta {
  font-size: 0.82rem;
  color: var(--text-muted);
}

/* Sections */
.section {
  padding: 4.5rem 0;
  border-top: 1px solid var(--border-subtle);
}

.section-header {
  max-width: 720px;
  margin-bottom: 2.5rem;
}

.section-eyebrow {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent-warm);
  margin-bottom: 0.5rem;
}

.section-header h2 {
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

.section-header p {
  color: var(--text-secondary);
  font-size: 1.05rem;
}

/* Interactive Chart Panel */
.panel {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 2rem;
  box-shadow: var(--shadow-lg);
}

.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-bottom: 1.75rem;
}

.tab-btn {
  padding: 0.6rem 1.1rem;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.tab-btn.active {
  background: rgba(251, 146, 60, 0.16);
  border-color: var(--accent-warm);
  color: var(--text-primary);
}

.chart-wrapper {
  width: 100%;
  overflow-x: auto;
  margin-bottom: 1.5rem;
}

.chart-svg {
  width: 100%;
  height: auto;
  min-width: 580px;
  display: block;
}

.timeline-Explorer {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1.5rem;
  align-items: center;
  background: rgba(6, 11, 20, 0.65);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
}

.slider-group label {
  display: flex;
  justify-content: space-between;
  font-size: 0.92rem;
  font-weight: 600;
  margin-bottom: 0.6rem;
}

input[type='range'] {
  width: 100%;
  accent-color: var(--accent-warm);
  cursor: pointer;
}

.decade-summary {
  min-width: 240px;
  text-align: right;
}

.decade-year {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--accent-warm);
}

.decade-desc {
  font-size: 0.88rem;
  color: var(--text-secondary);
}

/* Causes & Sectors */
.two-col {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.75rem;
}

.sector-list {
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
}

.sector-item {
  background: rgba(6, 11, 20, 0.55);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 1rem 1.2rem;
}

.sector-top {
  display: flex;
  justify-content: space-between;
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: 0.45rem;
}

.sector-bar-bg {
  height: 8px;
  background: rgba(255, 255, 255, 0.07);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 0.45rem;
}

.sector-bar-fill {
  height: 100%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent-warm), var(--accent-hot));
}

.sector-note {
  font-size: 0.83rem;
  color: var(--text-secondary);
}

.gas-cards {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.gas-card {
  background: rgba(6, 11, 20, 0.55);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 1.2rem;
}

.gas-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 0.4rem;
}

.gas-formula {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--accent-cool);
}

.gas-badge {
  font-size: 0.78rem;
  padding: 0.2rem 0.6rem;
  border-radius: 999px;
  background: rgba(56, 189, 248, 0.14);
  color: #7dd3fc;
}

/* Scenarios */
.scenario-buttons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-bottom: 1.75rem;
}

.scenario-btn {
  text-align: left;
  padding: 1.25rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  background: rgba(6, 11, 20, 0.6);
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.2s ease;
}

.scenario-btn.active {
  border-color: var(--accent-warm);
  background: rgba(251, 146, 60, 0.14);
  box-shadow: 0 10px 25px -10px rgba(251, 146, 60, 0.4);
}

.scenario-temp {
  font-size: 1.65rem;
  font-weight: 800;
  margin-bottom: 0.25rem;
}

.scenario-name {
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: 0.2rem;
}

.scenario-sub {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.impact-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1.15rem;
}

.impact-box {
  background: rgba(6, 11, 20, 0.65);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 1.25rem;
}

.impact-title {
  font-size: 0.84rem;
  color: var(--text-secondary);
  margin-bottom: 0.4rem;
}

.impact-val {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
  color: var(--text-primary);
}

.impact-detail {
  font-size: 0.84rem;
  color: var(--text-muted);
}

/* Carbon Calculator */
.calc-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 2rem;
  align-items: start;
}

.calc-controls {
  display: flex;
  flex-direction: column;
  gap: 1.35rem;
}

.control-row {
  background: rgba(6, 11, 20, 0.55);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 1.1rem 1.25rem;
}

.control-header {
  display: flex;
  justify-content: space-between;
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
}

.control-val {
  color: var(--accent-warm);
}

.calc-result {
  background: linear-gradient(160deg, rgba(16, 26, 44, 0.95), rgba(6, 11, 20, 0.95));
  border: 1px solid var(--border-highlight);
  border-radius: var(--radius-md);
  padding: 1.75rem;
}

.footprint-total {
  font-size: 3rem;
  font-weight: 800;
  line-height: 1.1;
  color: var(--accent-warm);
  margin: 0.4rem 0 1rem;
}

.comparison-bars {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  margin: 1.25rem 0;
}

.comp-row {
  font-size: 0.85rem;
}

.comp-label {
  display: flex;
  justify-content: space-between;
  margin-bottom: 0.3rem;
  color: var(--text-secondary);
}

.comp-track {
  height: 10px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 999px;
  overflow: hidden;
}

.comp-fill {
  height: 100%;
  border-radius: 999px;
  transition: width 0.3s ease;
}

.tip-box {
  margin-top: 1.25rem;
  padding: 1rem;
  border-radius: var(--radius-sm);
  background: rgba(16, 185, 129, 0.1);
  border: 1px solid rgba(16, 185, 129, 0.3);
  font-size: 0.88rem;
  color: #a7f3d0;
}

/* Solutions Grid */
.solutions-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.25rem;
}

.solution-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.6rem;
  transition: transform 0.2s ease, border-color 0.2s ease;
}

.solution-card:hover {
  transform: translateY(-3px);
  border-color: rgba(16, 185, 129, 0.45);
}

.solution-tag {
  display: inline-block;
  font-size: 0.76rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  background: rgba(16, 185, 129, 0.15);
  color: #6ee7b7;
  margin-bottom: 0.9rem;
}

.solution-card h3 {
  font-size: 1.18rem;
  margin-bottom: 0.55rem;
}

.solution-card p {
  font-size: 0.92rem;
  color: var(--text-secondary);
}

/* Footer */
.footer {
  border-top: 1px solid var(--border-subtle);
  padding: 3rem 0;
  color: var(--text-muted);
  font-size: 0.88rem;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem;
}

@media (max-width: 820px) {
  .nav-links {
    display: none;
  }
  .calc-grid {
    grid-template-columns: 1fr;
  }
  .timeline-Explorer {
    grid-template-columns: 1fr;
  }
  .decade-summary {
    text-align: left;
  }
}