:root {
  --ink: #172026;
  --muted: #60707f;
  --line: #d8e2ea;
  --paper: #ffffff;
  --soft: #f4f8fb;
  --brand: #0f766e;
  --brand-2: #2563eb;
  --accent: #b45309;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background: var(--soft);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", Arial, sans-serif;
  line-height: 1.68;
}

a { color: var(--brand); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 14px 5vw;
  background: rgba(255, 255, 255, .96);
  border-bottom: 1px solid var(--line);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 9px;
  color: #fff;
  font-weight: 800;
  background: var(--brand);
}

.brand strong { display: block; font-size: 18px; line-height: 1.15; }
.brand small { display: block; color: var(--muted); font-size: 12px; }

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 14px;
}

nav a {
  color: var(--ink);
  text-decoration: none;
  font-weight: 700;
}

main {
  width: min(1180px, 90vw);
  margin: 0 auto;
}

.hero {
  min-height: 540px;
  display: grid;
  grid-template-columns: minmax(0, 1.08fr) minmax(320px, .92fr);
  gap: 44px;
  align-items: center;
  padding: 54px 0 36px;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--brand);
  font-weight: 800;
  letter-spacing: 0;
}

h1, h2, h3 { line-height: 1.25; letter-spacing: 0; }

h1 {
  margin: 0;
  max-width: 760px;
  font-size: 48px;
}

.lead {
  max-width: 760px;
  color: var(--muted);
  font-size: 18px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  padding: 10px 16px;
  border-radius: 7px;
  color: #fff;
  background: var(--brand);
  font-weight: 800;
  text-decoration: none;
}

.button.secondary {
  color: var(--brand);
  background: #e6f4f1;
}

.gene-visual {
  min-height: 360px;
  display: grid;
  place-items: center;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.gene-visual svg {
  width: min(100%, 420px);
  height: auto;
}

.gene-visual .helix {
  fill: none;
  stroke: url(#g1);
  stroke-width: 12;
  stroke-linecap: round;
}

.gene-visual .helix.alt { opacity: .62; }
.gene-visual .rungs line { stroke: #8fb5c9; stroke-width: 8; stroke-linecap: round; }
.gene-visual circle, .gene-visual rect { fill: #e8f3ff; stroke: #89b7df; stroke-width: 3; }
.gene-visual text { fill: var(--muted); font-size: 15px; font-weight: 700; }

.section-strip {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 10px;
  padding: 12px 0 28px;
}

.section-strip a {
  min-height: 74px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  padding: 12px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--ink);
  text-decoration: none;
  font-weight: 800;
}

.section-strip span {
  color: var(--brand);
  font-size: 13px;
}

.content-section {
  padding: 32px 0;
  border-top: 1px solid var(--line);
}

.section-head {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 18px;
}

h2 {
  margin: 0;
  font-size: 30px;
}

.article-list {
  display: grid;
  gap: 18px;
}

.article-card, .mini-panel, .tool-card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 22px;
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
}

.article-card h3 {
  margin: 10px 0 12px;
  font-size: 24px;
}

.article-card p { margin: 10px 0; }

.takeaway {
  margin: 16px 0;
  padding: 12px 14px;
  border-left: 4px solid var(--accent);
  background: #fff8ed;
}

.sources {
  color: var(--muted);
  font-size: 14px;
}

.two-col {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 420px);
  gap: 22px;
  align-items: start;
}

.link-list, .mini-panel ol {
  margin: 0;
  padding-left: 22px;
}

.link-list li, .mini-panel li { margin: 8px 0; }

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

.tool-card {
  display: block;
  color: var(--ink);
  text-decoration: none;
}

.tool-card strong {
  display: block;
  margin-bottom: 8px;
  font-size: 18px;
}

.tool-card span {
  color: var(--muted);
}

.site-footer {
  margin-top: 28px;
  padding: 28px 5vw;
  text-align: center;
  color: var(--muted);
  border-top: 1px solid var(--line);
  background: #fff;
}

.site-footer p { margin: 6px 0; }

@media (max-width: 860px) {
  .site-header { align-items: flex-start; flex-direction: column; }
  .hero { grid-template-columns: 1fr; min-height: auto; }
  h1 { font-size: 36px; }
  .section-strip { grid-template-columns: repeat(2, 1fr); }
  .two-col, .tool-grid { grid-template-columns: 1fr; }
}

@media (max-width: 520px) {
  main { width: min(100% - 28px, 1180px); }
  h1 { font-size: 30px; }
  .section-strip { grid-template-columns: 1fr; }
  .gene-visual { min-height: 280px; }
}