@import url("https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&family=IBM+Plex+Mono:wght@400;600&display=swap");

:root {
  --bg: #f6f4ef;
  --ink: #0f1418;
  --muted: #5b6168;
  --card: #ffffff;
  --accent: #d65a3a;
  --line: #e2ded6;
  --deep: #0b2a3c;
  --sea: #1765a3;
  --sun: #f4b942;
  --sky: #c7e3ff;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: "Space Grotesk", system-ui, -apple-system, sans-serif;
  color: var(--ink);
  background:
    radial-gradient(1200px 600px at 85% -10%, #fff 0%, rgba(255,255,255,0) 60%),
    linear-gradient(180deg, #f8f7f2, #f2f0e8);
}

.top-nav {
  position: sticky;
  top: 0;
  z-index: 30;
  background: rgba(248, 247, 242, 0.9);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(10px);
}

.nav-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 12px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  font-weight: 700;
  letter-spacing: 0.02em;
}

.nav-links {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  font-size: 0.95rem;
}

.nav-links a {
  padding: 6px 10px;
  border-radius: 999px;
  border: 1px solid transparent;
}

.nav-links a:hover {
  background: #fff;
  border-color: var(--line);
}

.nav-toggle {
  display: none;
  border: 1px solid var(--line);
  background: #fff;
  padding: 6px 12px;
  border-radius: 999px;
  font-weight: 600;
  cursor: pointer;
}

.hero {
  background:
    radial-gradient(1200px 420px at 8% -10%, #fff4e6 0%, rgba(255,255,255,0.4) 55%, transparent 100%),
    linear-gradient(120deg, rgba(23,101,163,0.12), rgba(214,90,58,0.10));
  border-bottom: 1px solid var(--line);
}

.hero-inner {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 28px;
  padding: 40px 24px 32px;
  max-width: 1200px;
  margin: 0 auto;
}

.kicker {
  font-size: 0.85rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 8px;
}

.hero h1 {
  font-size: clamp(2.2rem, 5vw, 3.1rem);
  margin: 0 0 10px;
}

.lead {
  font-size: clamp(1rem, 2.2vw, 1.15rem);
  color: #333;
  line-height: 1.6;
  margin-bottom: 16px;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  font-size: 0.9rem;
  color: var(--muted);
}

.hero-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 18px;
  box-shadow: 0 10px 24px rgba(0,0,0,0.06);
  position: relative;
  overflow: hidden;
}

.hero-card::after {
  content: "";
  position: absolute;
  inset: auto -40px -60px auto;
  width: 220px;
  height: 220px;
  background: radial-gradient(circle, rgba(31,119,180,0.18), transparent 60%);
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
  margin-top: 14px;
}

.hero-stats div {
  background: #f7f5f0;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 8px;
  text-align: center;
}

.hero-stats strong {
  display: block;
  font-size: 1.1rem;
  color: var(--deep);
}

.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 24px;
}

section { margin: 32px 0; }
section h2 {
  margin-bottom: 12px;
  font-size: 1.8rem;
  position: relative;
  padding-bottom: 6px;
}

section h2::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 56px;
  height: 3px;
  background: var(--accent);
  border-radius: 999px;
}

a {
  color: var(--deep);
  text-decoration: none;
}

a:hover { text-decoration: underline; }

.grid {
  display: grid;
  gap: 16px;
}

.grid.two { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid.three { grid-template-columns: repeat(3, minmax(0, 1fr)); }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 16px;
  box-shadow: 0 6px 16px rgba(0,0,0,0.05);
}

.card-link {
  display: block;
  color: inherit;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}

.card-link:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 20px rgba(0,0,0,0.08);
  border-color: #d8d2c7;
}

.card-caption {
  margin-top: 10px;
  font-weight: 600;
  color: var(--ink);
}

.card.pad-lg {
  padding: 20px;
}

.card.dark {
  background: #0f1f2b;
  color: #f4f7f9;
  border-color: #1b2c3a;
}

.card.dark .note,
.card.dark small,
.card.dark label {
  color: #c7d2da;
}

.soft-section {
  background: #fffaf1;
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 18px;
}

.card img {
  width: 100%;
  height: auto;
  border-radius: 10px;
}

.zoomable {
  cursor: zoom-in;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.zoomable:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 18px rgba(0,0,0,0.08);
}

.lightbox {
  position: fixed;
  inset: 0;
  background: rgba(10,14,18,0.8);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 999;
}

.lightbox.open { display: flex; }

.lightbox img {
  max-width: 92vw;
  max-height: 92vh;
  border-radius: 12px;
  background: #fff;
  padding: 8px;
}

figcaption { margin-top: 8px; color: var(--muted); }

.note { color: var(--muted); font-size: 0.95rem; }

.footer {
  border-top: 1px solid var(--line);
  padding: 18px 24px;
  text-align: center;
  color: var(--muted);
}

@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; }
  .grid.two, .grid.three { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .nav-inner {
    padding: 10px 14px;
    gap: 10px;
  }

  .brand {
    font-size: 1rem;
  }

  .nav-links {
    display: none;
    flex-direction: column;
    align-items: flex-start;
    width: 100%;
    gap: 8px;
    padding: 8px 0 4px;
  }

  .nav-links.open {
    display: flex;
  }

  .nav-links a {
    font-size: 0.9rem;
    padding: 6px 8px;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .hero-inner {
    padding: 28px 16px 24px;
  }

  .hero h1 {
    font-size: clamp(2rem, 6vw, 2.6rem);
  }

  .lead {
    font-size: 1rem;
  }

  .meta {
    font-size: 0.85rem;
  }

  .container {
    padding: 16px;
  }

  section {
    margin: 24px 0;
  }

  section h2 {
    font-size: 1.4rem;
  }

  .card,
  .hero-card {
    padding: 14px;
  }

  .hero-stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .panel-media img {
    max-height: 240px;
  }

  .formula {
    font-size: 0.85rem;
  }

  .tab {
    padding: 6px 10px;
    font-size: 0.9rem;
  }
}

@media (max-width: 480px) {
  .hero-stats {
    grid-template-columns: 1fr;
  }

  .meta {
    flex-direction: column;
  }
}

@media (max-width: 900px) {
  .tabs {
    display: none;
  }

  .panel {
    display: block;
    margin-bottom: 16px;
    border: 1px solid var(--line);
    border-radius: 14px;
    background: var(--card);
    padding: 12px;
    box-shadow: 0 6px 16px rgba(0,0,0,0.04);
  }

  .panel:last-child {
    margin-bottom: 0;
  }
}

.formula {
  background: #0f0f0f;
  color: #f4f4f4;
  padding: 14px;
  border-radius: 10px;
  font-family: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.95rem;
  overflow-x: auto;
}

.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 14px;
}

.tab {
  border: 1px solid var(--line);
  background: #fff;
  padding: 8px 14px;
  border-radius: 999px;
  cursor: pointer;
  font-weight: 600;
}

.tab.active {
  background: var(--ink);
  color: #fff;
  border-color: var(--ink);
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip {
  padding: 6px 10px;
  border-radius: 999px;
  background: #f3f1ec;
  border: 1px solid var(--line);
  font-size: 0.85rem;
}

.panel {
  display: none;
}

.panel.active {
  display: block;
}

.panel-grid {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 16px;
}

.panel-text {
  font-size: 0.98rem;
  line-height: 1.55;
}

.panel-text code {
  display: inline-block;
  margin-top: 6px;
  font-size: 0.85rem;
  color: var(--muted);
}

.panel-media {
  display: grid;
  gap: 12px;
}

.panel-media img {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 6px;
  max-height: 300px;
  object-fit: contain;
}

.panel-media .media-wide {
  max-height: 420px;
}

.panel-media .media-small {
  max-height: 280px;
}

.media-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.model-summary {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.model-summary .card h3 {
  margin-top: 0;
}

.metric-help {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.metric-pill {
  background: #f7f5f0;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 10px;
}

.metric-pill strong {
  display: block;
  color: var(--deep);
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin: 10px 0 6px;
}

.stat {
  background: #f7f5f0;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 10px 12px;
}

.stat small {
  display: block;
  font-size: 0.85rem;
  color: var(--muted);
}

.stat strong {
  display: block;
  font-size: 1.05rem;
  color: var(--deep);
}

.link-list {
  margin: 8px 0 0;
  padding-left: 18px;
}

.link-list li {
  margin: 4px 0;
}

@media (max-width: 900px) {
  .panel-grid { grid-template-columns: 1fr; }
  .media-row { grid-template-columns: 1fr; }
  .panel-media img { max-height: none; }
  .model-summary { grid-template-columns: 1fr; }
  .metric-help { grid-template-columns: 1fr; }
  .stat-grid { grid-template-columns: 1fr; }
}

label {
  display: block;
  font-weight: 600;
  margin-top: 10px;
}

select,
input[type="range"] {
  width: 100%;
  margin: 6px 0 4px;
}

input[type="range"] {
  accent-color: var(--accent);
}

select {
  padding: 8px 10px;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: #fff;
}

.row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.btn {
  appearance: none;
  border: 1px solid var(--line);
  background: #fff;
  padding: 8px 12px;
  border-radius: 999px;
  font-weight: 600;
  cursor: pointer;
}

.btn.primary {
  background: var(--deep);
  color: #fff;
  border-color: var(--deep);
}

.btn.ghost {
  background: transparent;
}

.chip-group {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.chip-btn {
  border: 1px solid var(--line);
  background: #f8f7f3;
  padding: 6px 10px;
  border-radius: 999px;
  font-size: 0.85rem;
  cursor: pointer;
}

.chip-btn:hover {
  background: #fff;
}

.value {
  font-size: 0.9rem;
  color: var(--muted);
  margin-bottom: 4px;
}

.sim-layout {
  display: grid;
  gap: 16px;
}

.sim-controls {
  display: grid;
  gap: 8px;
}

.sim-cta {
  background: linear-gradient(140deg, var(--deep), #214a63);
  color: #fff;
  border-radius: 12px;
  padding: 12px;
  font-size: 0.95rem;
}

.sim-metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-top: 10px;
}

.sim-params {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
  font-size: 0.9rem;
  margin-top: 8px;
}

.metric {
  background: #f8f7f3;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px;
  text-align: center;
}

.metric strong {
  display: block;
  font-size: 1.1rem;
  color: var(--deep);
}

.sim-chart {
  background: #f9f8f5;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 10px;
  position: relative;
}

.sim-chart svg {
  height: 520px;
}

.sim-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.sim-grid .card {
  height: 100%;
}

@media (max-width: 1000px) {
  .sim-grid { grid-template-columns: 1fr; }
}

.legend {
  margin-top: 8px;
  font-size: 0.9rem;
  color: var(--muted);
  display: flex;
  gap: 12px;
  align-items: center;
  flex-wrap: wrap;
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 999px;
  display: inline-block;
  margin-right: 6px;
}

.dot.base { background: #333; }
.dot.adj { background: #d55e00; }

.loss-bar {
  display: flex;
  height: 28px;
  border-radius: 999px;
  overflow: hidden;
  margin-top: 12px;
  border: 1px solid var(--line);
}

#loss-use {
  background: var(--sea);
  color: #fff;
  font-size: 0.8rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

#loss-evap {
  background: #d55e00;
  color: #fff;
  font-size: 0.8rem;
  display: flex;
  align-items: center;
  justify-content: center;
}


.assumptions {
  background: #fff7eb;
  border: 1px dashed #d55e00;
  border-radius: 10px;
  padding: 10px;
  margin-top: 12px;
  font-size: 0.9rem;
}

.sim-metrics {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-top: 10px;
}

.metric {
  background: #f8f7f3;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px;
  text-align: center;
}

.metric strong {
  display: block;
  font-size: 1.1rem;
  color: var(--deep);
}

.section-banner {
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 18px;
  background: linear-gradient(120deg, rgba(23,101,163,0.08), rgba(214,90,58,0.06));
  margin-bottom: 16px;
}

.baseline {
  background: #f7f6f1;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px;
  margin-top: 12px;
}

.baseline ul {
  padding-left: 18px;
  margin: 8px 0;
}

.flow {
  display: grid;
  gap: 10px;
}

.flow-step {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 10px;
  align-items: center;
  padding: 10px 12px;
  border-radius: 12px;
  background: #f8f7f3;
  border: 1px solid var(--line);
}

.flow-step span {
  display: inline-flex;
  width: 30px;
  height: 30px;
  border-radius: 999px;
  align-items: center;
  justify-content: center;
  background: var(--ink);
  color: #fff;
  font-weight: 700;
}

.tooltip {
  position: absolute;
  pointer-events: none;
  background: #0b2a3c;
  color: #fff;
  padding: 6px 8px;
  font-size: 0.85rem;
  border-radius: 8px;
  opacity: 0;
  transform: translate(-50%, -110%);
  white-space: nowrap;
  line-height: 1.35;
}

.sim-svg {
  width: 100%;
  height: 360px;
}

@media (max-width: 1000px) {
  .sim-layout { grid-template-columns: 1fr; }
  .sim-metrics { grid-template-columns: 1fr; }
  .nav-inner { flex-direction: column; align-items: flex-start; }
  .hero-stats { grid-template-columns: 1fr; }
}