:root {
  --paper: #f6f5f2;
  --surface: #ffffff;
  --ink: #1a1a1a;
  --muted: #6b6660;
  --faint: #8a8780;
  --accent: #1a5a68;
  --line: rgba(26, 26, 26, 0.08);
  --serif: "Songti SC", "Source Han Serif SC", "Noto Serif SC", "Times New Roman", serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Helvetica Neue", sans-serif;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.wrap {
  width: min(720px, calc(100% - 40px));
  margin: 0 auto;
  padding: 48px 0 72px;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 56px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: inherit;
  text-decoration: none;
}

.brand img {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--surface);
  box-shadow: 0 1px 0 var(--line);
}

.brand-name {
  font-family: var(--serif);
  font-size: 22px;
  letter-spacing: 0.12em;
}

nav { display: flex; gap: 18px; font-size: 14px; color: var(--muted); }
nav a { color: var(--muted); }

.hero { text-align: left; }
.kicker {
  color: var(--accent);
  font-size: 13px;
  letter-spacing: 0.08em;
  margin: 0 0 12px;
}
h1 {
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(34px, 6vw, 48px);
  line-height: 1.25;
  margin: 0 0 16px;
}
.lead {
  color: var(--muted);
  font-size: 18px;
  max-width: 34em;
  margin: 0 0 12px;
}
.lead-en {
  color: var(--faint);
  font-size: 15px;
  max-width: 36em;
  margin: 0 0 28px;
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.pill {
  border: 1px solid var(--line);
  background: var(--surface);
  color: var(--muted);
  font-size: 13px;
  padding: 6px 10px;
  border-radius: 999px;
}

.features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin: 48px 0;
}
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 20px 18px;
}
.card h2 {
  font-size: 16px;
  margin: 0 0 8px;
}
.card p {
  margin: 0;
  color: var(--muted);
  font-size: 14px;
}

.block h2 {
  font-family: var(--serif);
  font-size: 22px;
  font-weight: 500;
  margin: 0 0 12px;
}
.block p, .block li { color: var(--muted); }
.block ol { padding-left: 1.2em; }
.block li { margin: 6px 0; }

footer {
  margin-top: 56px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  color: var(--faint);
  font-size: 13px;
}
footer p { margin: 6px 0; }

.doc h1 { font-size: 32px; margin-bottom: 8px; }
.doc .updated { color: var(--faint); font-size: 13px; margin-bottom: 28px; }
.doc h2 { font-family: var(--serif); font-size: 20px; font-weight: 500; margin: 28px 0 8px; }
.doc p { color: var(--muted); }

@media (max-width: 640px) {
  .features { grid-template-columns: 1fr; }
  header { align-items: flex-start; flex-direction: column; }
}