:root {
  color-scheme: light;
  --ink: #1c2529;
  --muted: #647177;
  --line: #dfe5e7;
  --paper: #ffffff;
  --canvas: #f4f6f5;
  --brand: #0f766e;
}

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

body {
  margin: 0;
  color: var(--ink);
  background: var(--canvas);
  font-family: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  line-height: 1.75;
}

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

.document {
  width: min(780px, calc(100% - 28px));
  margin: 0 auto;
  padding: 32px 0 56px;
}

.document__header {
  padding: 28px;
  background: var(--paper);
  border-top: 4px solid var(--brand);
  border-radius: 8px;
}

.document__tag {
  margin: 0 0 8px;
  color: var(--brand);
  font-size: 13px;
  font-weight: 700;
}

h1 {
  margin: 0;
  font-family: "STSong", "Songti SC", serif;
  font-size: clamp(30px, 6vw, 44px);
  line-height: 1.2;
}

.document__summary {
  margin: 14px 0 0;
  color: var(--muted);
}

.document__meta {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.section {
  margin-top: 12px;
  padding: 24px 28px;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 8px;
}

.section h2 {
  margin: 0 0 12px;
  font-size: 18px;
}

.section p {
  margin: 10px 0 0;
  color: #344147;
  font-size: 15px;
}

.document__footer {
  padding: 28px 12px 0;
  color: var(--muted);
  font-size: 13px;
  text-align: center;
}

@media (max-width: 520px) {
  .document {
    width: min(100% - 20px, 780px);
    padding-top: 10px;
  }

  .document__header,
  .section {
    padding: 21px 18px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
  }
}