:root {
  --ink: #1e2220;
  --muted: #666e6a;
  --paper: #f7f7f3;
  --line: #deded6;
  --red: #8c1d22;
}

* { box-sizing: border-box; }

html {
  background: var(--paper);
  color: var(--ink);
  font: 16px/1.6 ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

body { margin: 0; }

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

.top {
  align-items: center;
  border-bottom: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  padding: 20px 6vw;
}

.mark {
  color: var(--red);
  font-weight: 800;
  margin: 0;
}

nav {
  display: flex;
  gap: 20px;
}

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

nav a:hover { color: var(--red); }

main {
  margin: 0 auto;
  max-width: 920px;
  padding: 84px 6vw;
}

.home {
  min-height: 100svh;
  padding-top: 28svh;
}

h1 {
  font-size: 52px;
  letter-spacing: 0;
  line-height: 1.05;
  margin: 18px 0 16px;
  max-width: 760px;
}

h2 {
  border-top: 1px solid var(--line);
  font-size: 18px;
  margin: 52px 0 14px;
  padding-top: 22px;
}

p {
  color: var(--muted);
  max-width: 680px;
}

ul {
  color: var(--muted);
  list-style: none;
  margin: 0;
  padding: 0;
}

li {
  border-top: 1px solid var(--line);
  padding: 12px 0;
}

@media (max-width: 640px) {
  .top {
    align-items: flex-start;
    flex-direction: column;
    gap: 12px;
  }

  nav {
    flex-wrap: wrap;
    gap: 14px;
  }

  main { padding-top: 56px; }
  .home { padding-top: 22svh; }
  h1 { font-size: 34px; }
}