:root {
  --bg: #f7f4ed;
  --surface: rgba(255,255,255,0.88);
  --text: #15201c;
  --muted: #65736d;
  --line: rgba(21,32,28,0.14);
  --accent: #166b55;
  --shadow: 0 24px 70px rgba(20, 34, 29, 0.13);
  --radius: 28px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(22,107,85,.18), transparent 32rem),
    radial-gradient(circle at bottom right, rgba(221,169,82,.20), transparent 28rem),
    var(--bg);
}

.page {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 36px 0 64px;
}

.hero {
  padding: clamp(28px, 6vw, 64px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.eyebrow {
  display: inline-flex;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 9px 14px;
  color: var(--muted);
  font-weight: 800;
  letter-spacing: .04em;
  text-transform: uppercase;
  font-size: .78rem;
}

h1 {
  max-width: 880px;
  margin: 20px 0 16px;
  font-size: clamp(3rem, 10vw, 7.6rem);
  line-height: .86;
  letter-spacing: -.08em;
}

.lead {
  max-width: 780px;
  font-size: clamp(1.08rem, 2vw, 1.35rem);
  line-height: 1.65;
  color: var(--muted);
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

a {
  color: inherit;
}

.primary,
.secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  border-radius: 999px;
  padding: 0 18px;
  font-weight: 850;
  text-decoration: none;
}

.primary {
  background: var(--text);
  color: white;
}

.secondary {
  border: 1px solid var(--line);
  background: white;
}

.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-top: 18px;
}

article,
.formula,
.proof {
  border: 1px solid var(--line);
  border-radius: 22px;
  background: rgba(255,255,255,.78);
  padding: 22px;
}

article span {
  color: var(--accent);
  font-weight: 900;
}

article h2 {
  margin: 8px 0;
  font-size: 1.2rem;
}

article p,
.proof p,
.proof li {
  color: var(--muted);
  line-height: 1.55;
}

.formula,
.proof {
  margin-top: 18px;
}

pre {
  overflow-x: auto;
  padding: 18px;
  border-radius: 18px;
  background: #14201c;
  color: #fffaf0;
  line-height: 1.5;
}

@media (max-width: 860px) {
  .grid { grid-template-columns: 1fr; }
  .page { width: min(100% - 22px, 1120px); padding-top: 18px; }
}