:root {
  --yellow: #FACC15;
  --yellow-soft: #FDE68A;
  --yellow-deep: #CA8A04;
  --black: #0A0A0A;
  --ink: #111111;
  --panel: #141414;
  --line: #2A2A2A;
  --muted: #A3A3A3;
  --paper: #FFFBEB;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--black);
  color: var(--paper);
  line-height: 1.75;
}

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

.wrap { width: min(1120px, calc(100% - 32px)); margin: 0 auto; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: #000;
  border-bottom: 3px solid var(--yellow);
}

.header-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  min-height: 72px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--yellow);
  font-weight: 800;
  letter-spacing: 0.04em;
}

.brand-key {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: linear-gradient(#FDE047, var(--yellow));
  color: var(--black);
  display: grid;
  place-items: center;
  font-size: 14px;
  box-shadow: 0 3px 0 var(--yellow-deep), 0 6px 0 #000;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 14px;
  font-size: 14px;
}

.nav a { color: var(--paper); }
.nav a:hover { color: var(--yellow); }

.hero {
  padding: 56px 0 28px;
}

.hero-board {
  background: var(--panel);
  border: 2px solid var(--yellow);
  border-radius: 20px;
  padding: 36px 32px 28px;
  box-shadow: 8px 8px 0 var(--yellow);
}

.hero h1 {
  font-size: clamp(28px, 4vw, 40px);
  line-height: 1.35;
  color: var(--yellow);
  max-width: 18em;
}

.hero-lead {
  margin-top: 16px;
  max-width: 40em;
  color: #F5F5F4;
}

.key-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.mini-key {
  min-width: 56px;
  padding: 8px 12px;
  border-radius: 10px;
  background: linear-gradient(#FFF7CC, var(--yellow));
  color: var(--black);
  font-weight: 800;
  text-align: center;
  box-shadow: 0 4px 0 var(--yellow-deep);
}

.section { padding: 36px 0; }

.section h2 {
  font-size: clamp(22px, 3vw, 30px);
  color: var(--yellow);
  margin-bottom: 18px;
}

.section p { margin-bottom: 14px; color: #E7E5E4; }

.key-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin: 20px 0 8px;
}

.keycap {
  background: linear-gradient(#FFF4B0, var(--yellow));
  color: var(--ink);
  border-radius: 16px;
  padding: 22px 18px 18px;
  box-shadow: 0 6px 0 var(--yellow-deep), 0 10px 0 #000;
  min-height: 180px;
}

.keycap kbd {
  display: inline-block;
  background: var(--black);
  color: var(--yellow);
  border-radius: 8px;
  padding: 2px 8px;
  font-size: 12px;
  margin-bottom: 10px;
}

.keycap h3 { font-size: 18px; margin-bottom: 8px; }
.keycap p { color: #1C1917; margin: 0; font-size: 15px; }

.steps {
  display: grid;
  gap: 12px;
  margin: 18px 0;
}

.step {
  display: grid;
  grid-template-columns: 64px 1fr;
  gap: 14px;
  align-items: start;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 14px;
}

.step-index {
  width: 64px;
  height: 52px;
  border-radius: 12px;
  background: var(--yellow);
  color: var(--black);
  font-weight: 800;
  display: grid;
  place-items: center;
  box-shadow: 0 4px 0 var(--yellow-deep);
}

.table-wrap { overflow-x: auto; margin: 16px 0 8px; }

table {
  width: 100%;
  border-collapse: collapse;
  background: var(--panel);
}

th, td {
  border: 1px solid var(--line);
  padding: 12px 14px;
  text-align: left;
  vertical-align: top;
}

th { background: var(--yellow); color: var(--black); }

.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 16px 0;
}

.split article {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 16px;
}

.svg-card {
  background: var(--panel);
  border: 1px solid var(--yellow-deep);
  border-radius: 16px;
  padding: 16px;
  margin: 16px 0;
}

.faq-list { display: grid; gap: 12px; }

.faq-item {
  background: var(--panel);
  border-left: 6px solid var(--yellow);
  border-radius: 10px;
  padding: 14px 16px;
}

.faq-item h3 { color: var(--yellow-soft); font-size: 17px; margin-bottom: 6px; }

.site-footer {
  border-top: 3px solid var(--yellow);
  padding: 28px 0 40px;
  color: var(--muted);
  font-size: 14px;
}

.site-footer p { margin-bottom: 8px; }

@media (max-width: 860px) {
  .header-bar { flex-direction: column; align-items: flex-start; padding: 12px 0; }
  .key-grid, .split { grid-template-columns: 1fr; }
  .hero-board { box-shadow: 4px 4px 0 var(--yellow); }
}