:root {
  color-scheme: light;
  --ink: #24232a;
  --muted: #66656d;
  --surface: #ffffff;
  --line: #e7e6ec;
  --brand: #6870dd;
  --brand-soft: #e8eaff;
  --mint: #e1f4e8;
  --peach: #ffe7dc;
  --yellow: #fff0b6;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", sans-serif;
  color: var(--ink);
  background: #f8f8fb;
  letter-spacing: 0;
}

a { color: inherit; }

.shell {
  width: min(100% - 32px, 760px);
  margin: 0 auto;
}

.topbar {
  display: flex;
  min-height: 72px;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  font-weight: 700;
}

.brand img { width: 38px; height: 38px; object-fit: contain; }

.language {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  gap: 4px;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.language button {
  min-width: 48px;
  min-height: 36px;
  border: 0;
  border-radius: 6px;
  color: var(--muted);
  background: transparent;
  font: inherit;
  cursor: pointer;
}

.language button[aria-pressed="true"] {
  color: var(--ink);
  background: var(--brand-soft);
  font-weight: 650;
}

main { padding: 48px 0 72px; }

.eyebrow { margin: 0 0 12px; color: var(--brand); font-size: 15px; font-weight: 700; }

h1 { margin: 0; max-width: 680px; font-size: clamp(36px, 8vw, 56px); line-height: 1.08; }

.lead { margin: 22px 0 0; max-width: 670px; color: var(--muted); font-size: 18px; line-height: 1.7; }

.summary {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin: 40px 0;
}

.summary div {
  min-height: 112px;
  padding: 20px;
  border-radius: 8px;
  background: var(--brand-soft);
}

.summary div:nth-child(2) { background: var(--mint); }
.summary div:nth-child(3) { background: var(--yellow); }
.summary strong { display: block; margin-bottom: 8px; font-size: 17px; }
.summary span { color: var(--muted); font-size: 14px; line-height: 1.55; }

.content {
  padding: 32px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
}

.content section + section { margin-top: 34px; padding-top: 34px; border-top: 1px solid var(--line); }
.content h2 { margin: 0 0 12px; font-size: 22px; line-height: 1.3; }
.content p, .content li { color: var(--muted); font-size: 16px; line-height: 1.75; }
.content p { margin: 0; }
.content p + p { margin-top: 12px; }
.content ul { margin: 10px 0 0; padding-left: 22px; }
.content a { color: #4f57ba; text-underline-offset: 3px; }

.links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.links a {
  display: inline-flex;
  min-height: 44px;
  align-items: center;
  padding: 0 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface);
  text-decoration: none;
  font-weight: 650;
}

footer {
  padding: 28px 0 44px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 14px;
}

[data-lang="en"] { display: none; }
html.lang-en [data-lang="zh"] { display: none; }
html.lang-en [data-lang="en"] { display: revert; }

@media (max-width: 640px) {
  main { padding-top: 32px; }
  .summary { grid-template-columns: 1fr; }
  .summary div { min-height: 0; }
  .content { padding: 24px 20px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}