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

:root {
  --bg: #0a0a0a;
  --text: #ffffff;
  --muted: #9a9a9a;
  --muted-dim: #666666;
  --line: rgba(255, 255, 255, 0.1);
  --panel: rgba(255, 255, 255, 0.035);
  --font: 'Geist', 'SF Pro Display', -apple-system, system-ui, sans-serif;
  --mono: 'Geist Mono', 'SF Mono', monospace;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(ellipse 70% 45% at 50% 0%, rgba(100, 110, 150, 0.16), transparent 64%),
    var(--bg);
  color: var(--text);
  font-family: var(--font);
  letter-spacing: -0.01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

.page {
  width: min(940px, calc(100% - 40px));
  margin: 0 auto;
  padding: 40px 0 72px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding-bottom: 56px;
}

.brand {
  font-size: 18px;
  font-weight: 600;
}

.back {
  color: var(--muted);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  transition: color 0.2s ease;
}

.back:hover {
  color: var(--text);
}

.eyebrow {
  margin: 0 0 18px;
  color: var(--muted-dim);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  max-width: 820px;
  font-size: clamp(40px, 7vw, 84px);
  line-height: 0.95;
  font-weight: 400;
  letter-spacing: -0.04em;
}

.intro {
  margin: 28px 0 48px;
  max-width: 720px;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.7;
}

.doc {
  display: grid;
  gap: 20px;
}

section {
  padding: 28px;
  border: 1px solid var(--line);
  background: var(--panel);
}

h2 {
  margin: 0 0 14px;
  font-size: 24px;
  line-height: 1.2;
  font-weight: 400;
  letter-spacing: -0.025em;
}

p, li {
  color: var(--muted);
  font-size: 15px;
  line-height: 1.72;
}

p {
  margin: 0;
}

p + p {
  margin-top: 12px;
}

ul {
  margin: 0;
  padding-left: 22px;
}

li + li {
  margin-top: 8px;
}

.doc a {
  color: var(--text);
  border-bottom: 1px solid rgba(255, 255, 255, 0.3);
}

.note {
  color: var(--muted-dim);
  font-family: var(--mono);
  font-size: 12px;
  letter-spacing: 0.02em;
}

footer {
  margin-top: 52px;
  padding-top: 24px;
  border-top: 1px solid var(--line);
  color: var(--muted-dim);
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

@media (max-width: 640px) {
  .page {
    width: min(100% - 32px, 940px);
    padding-top: 28px;
  }

  .topbar {
    padding-bottom: 44px;
  }

  section {
    padding: 22px;
  }
}