:root {
  --bg: #faf9f6;
  --card: #ffffff;
  --ink: #1b1a18;
  --muted: #5f5b54;
  --line: #e6e2da;
  --accent: #3b5bdb;
  --soft: #f1efe9;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1b1a18;
    --card: #23221f;
    --ink: #ecebe7;
    --muted: #a8a49b;
    --line: #37352f;
    --accent: #8ea2ff;
    --soft: #2b2a26;
    color-scheme: dark;
  }
  .diagram { background: #fbfaf7; }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.7 -apple-system, "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Segoe UI", sans-serif;
}

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

.wrap { max-width: 1040px; margin: 0 auto; padding: 0 20px; }

header.top {
  display: flex; justify-content: space-between; align-items: center;
  padding: 18px 0; font-size: 15px;
}
header.top .brand { font-weight: 650; color: var(--ink); }
header.top nav a { margin-left: 18px; color: var(--muted); }

.hero { padding: 48px 0 28px; }
.hero h1 { font-size: clamp(30px, 5vw, 44px); line-height: 1.2; margin: 0 0 14px; letter-spacing: -0.01em; }
.hero p.lead { font-size: 18px; color: var(--muted); max-width: 760px; margin: 0 0 24px; }

.actions { display: flex; flex-wrap: wrap; gap: 10px; }
.btn {
  display: inline-block; padding: 9px 16px; border-radius: 10px; border: 1px solid var(--line);
  background: var(--card); color: var(--ink); font-size: 15px;
}
.btn.primary { background: var(--ink); color: var(--bg); border-color: var(--ink); }
.btn:hover { text-decoration: none; border-color: var(--muted); }

.stats {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 10px;
  margin: 28px 0 0;
}
.stat { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 12px 14px; }
.stat b { display: block; font-size: 22px; }
.stat span { color: var(--muted); font-size: 13px; }

section { padding: 34px 0; border-top: 1px solid var(--line); }
section h2 { font-size: 24px; margin: 0 0 6px; }
section p.sub { color: var(--muted); margin: 0 0 20px; }

.shot { width: 100%; border-radius: 12px; border: 1px solid var(--line); display: block; }
.video { position: relative; width: 100%; aspect-ratio: 16 / 9; border-radius: 12px; overflow: hidden; border: 1px solid var(--line); background: #000; }
.video iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
.caption { color: var(--muted); font-size: 13px; margin: 8px 0 0; }

.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 14px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 16px 18px; }
.card h3 { margin: 0 0 6px; font-size: 17px; }
.card p { margin: 0; color: var(--muted); font-size: 15px; }
.card p + p { margin-top: 8px; }
.card .trust { color: var(--ink); }

.diagram { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 14px; }
.diagram img { width: 100%; display: block; }
.diagram.narrow img { max-width: 620px; margin: 0 auto; }

table { width: 100%; border-collapse: collapse; font-size: 15px; }
th, td { text-align: left; vertical-align: top; padding: 10px 12px; border-bottom: 1px solid var(--line); }
th { color: var(--muted); font-weight: 600; font-size: 13px; }
.table-scroll { overflow-x: auto; background: var(--card); border: 1px solid var(--line); border-radius: 12px; }
.num { white-space: nowrap; font-weight: 600; }

ul.plain { margin: 0; padding-left: 20px; }
ul.plain li { margin: 4px 0; }

footer { padding: 30px 0 50px; color: var(--muted); font-size: 14px; border-top: 1px solid var(--line); }

@media (max-width: 600px) {
  header.top nav a { margin-left: 12px; }
  .hero { padding-top: 24px; }
  th, td { padding: 8px; }
}