:root {
  --bg: #fbfcfe; --surface: #ffffff; --text: #12223a; --muted: #55667c;
  --line: #e2e7ee; --teal: #2a9d8f; --coral: #e76f51; --gold: #e9c46a;
  --link: #1f7a6f;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #0e1726; --surface: #152136; --text: #e8edf4; --muted: #9aa8bb;
    --line: #26344c; --link: #5cc8ba; }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; }
a { color: var(--link); }
.wrap { max-width: 960px; margin: 0 auto; padding: 0 20px; }
header { display: flex; align-items: center; justify-content: space-between; padding: 20px 0; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 20px; color: var(--text); text-decoration: none; }
.brand img { width: 32px; height: 32px; }
nav a { margin-left: 18px; color: var(--muted); text-decoration: none; font-size: 15px; }
nav a:hover { color: var(--text); }
.hero { padding: 48px 0 32px; text-align: center; }
.hero h1 { font-size: clamp(32px, 6vw, 52px); line-height: 1.15; margin: 0 0 16px; letter-spacing: -0.02em; }
.hero p { font-size: 19px; color: var(--muted); max-width: 640px; margin: 0 auto 28px; }
.btns { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.btn { display: inline-block; padding: 11px 22px; border-radius: 8px; font-weight: 600; text-decoration: none; }
.btn.primary { background: var(--teal); color: #fff; }
.btn.secondary { border: 1px solid var(--line); color: var(--text); background: var(--surface); }
.tags { margin-top: 22px; color: var(--muted); font-size: 14px; }
.figure { text-align: center; margin: 24px 0 8px; }
.figure img { max-width: 100%; height: auto; }
section { padding: 40px 0; border-top: 1px solid var(--line); }
section h2 { font-size: 28px; margin: 0 0 12px; letter-spacing: -0.01em; }
.lead { color: var(--muted); max-width: 680px; }
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; margin-top: 20px; }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 20px; }
.card h3 { margin: 0 0 6px; font-size: 18px; }
.card .kicker { font-size: 13px; font-weight: 600; text-transform: uppercase; letter-spacing: .06em; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }
.k1 { color: var(--teal); } .k2 { color: var(--coral); } .k3 { color: #c99a2e; }
ul.facts { padding-left: 20px; } ul.facts li { margin: 4px 0; }
pre { background: var(--surface); border: 1px solid var(--line); border-radius: 10px; padding: 16px; overflow-x: auto; font-size: 14px; line-height: 1.5; }
code { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }
.note { font-size: 14px; color: var(--muted); }
footer { padding: 32px 0 48px; border-top: 1px solid var(--line); color: var(--muted); font-size: 14px; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 8px; }
.dark-only { display: none; }
@media (prefers-color-scheme: dark) { .dark-only { display: inline; } .light-only { display: none; } }
@media (max-width: 560px) { nav > a { display: none; } .lang { margin-left: 0; } }
.lang { display: flex; gap: 4px; font-size: 14px; margin-left: 18px; }
.lang a { margin: 0; padding: 2px 6px; border-radius: 6px; }
.lang a[aria-current] { color: var(--text); background: var(--surface); border: 1px solid var(--line); }
nav { display: flex; align-items: center; }
:lang(zh-CN) body, body:lang(zh-CN) { font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Noto Sans CJK SC", sans-serif; }
:lang(ja) body, body:lang(ja) { font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic UI", "Meiryo", "Noto Sans CJK JP", sans-serif; }
.hero h1 span { display: inline-block; }