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

:root {
  --primary: #667eea;
  --primary-dark: #5568d3;
  --bg: #fff;
  --bg-alt: #f7f8fc;
  --text: #333;
  --text-light: #666;
  --text-muted: #999;
  --border: #e8e8f0;
  --radius: 10px;
}

body {
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
}

.container { max-width: 960px; margin: 0 auto; padding: 0 20px; }

/* Header */
.header {
  background: linear-gradient(135deg, var(--primary) 0%, #764ba2 100%);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 100;
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 0;
  flex-wrap: wrap;
  gap: 10px;
}
.logo { font-size: 18px; font-weight: 700; }
.nav { display: flex; align-items: center; gap: 18px; }
.nav a { color: rgba(255,255,255,0.85); text-decoration: none; font-size: 14px; transition: color 0.2s; }
.nav a:hover { color: #fff; }
.lang-btn {
  background: rgba(255,255,255,0.15);
  color: #fff;
  border: 1px solid rgba(255,255,255,0.3);
  border-radius: 4px;
  padding: 4px 12px;
  font-size: 12px;
  font-weight: 600;
  cursor: pointer;
  font-family: inherit;
  transition: background 0.2s;
}
.lang-btn:hover { background: rgba(255,255,255,0.25); }

/* Hero */
.hero {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  text-align: center;
  padding: 80px 20px;
}
.hero-title { font-size: 36px; font-weight: 800; margin-bottom: 16px; }
.hero-sub { font-size: 16px; opacity: 0.9; line-height: 1.8; margin-bottom: 24px; }
.hero-badges { display: flex; justify-content: center; gap: 12px; flex-wrap: wrap; }
.hero-badges span {
  background: rgba(255,255,255,0.15);
  border: 1px solid rgba(255,255,255,0.25);
  border-radius: 20px;
  padding: 6px 18px;
  font-size: 13px;
}

/* Section */
.section { padding: 64px 20px; }
.section.alt { background: var(--bg-alt); }
.section-title { font-size: 24px; font-weight: 700; text-align: center; margin-bottom: 36px; color: var(--primary); }
.subsection-title { font-size: 16px; font-weight: 600; margin: 28px 0 14px; color: var(--text); }

/* Cards */
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 20px; }
.card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 22px;
  text-align: center;
  transition: box-shadow 0.2s, transform 0.2s;
}
.card:hover { box-shadow: 0 4px 20px rgba(102,126,234,0.15); transform: translateY(-2px); }
.card-icon { font-size: 36px; margin-bottom: 12px; }
.card h4 { font-size: 16px; font-weight: 600; margin-bottom: 8px; }
.card p { font-size: 13px; color: var(--text-light); }

/* Steps */
.steps { display: flex; flex-direction: column; gap: 20px; }
.step { display: flex; gap: 16px; align-items: flex-start; }
.step-num {
  width: 36px; height: 36px;
  background: var(--primary);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 16px;
  flex-shrink: 0;
}
.step h4 { font-size: 15px; margin-bottom: 4px; }
.step p { font-size: 13px; color: var(--text-light); }
.step code {
  background: #f0f0f5;
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 12px;
}

/* Usage list */
.usage-list { padding-left: 20px; }
.usage-list li { margin-bottom: 10px; font-size: 14px; }
.note {
  background: #f0f4ff;
  border-left: 3px solid var(--primary);
  border-radius: 4px;
  padding: 12px 16px;
  font-size: 13px;
  color: var(--text-light);
  margin: 16px 0;
}

/* Guest grid */
.guest-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 10px;
}
.guest-grid > div {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 12px 14px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
}
.guest-grid > div span { color: var(--text-light); }

/* Platforms */
.platforms { display: flex; gap: 16px; flex-wrap: wrap; justify-content: center; }
.platform {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 28px;
  text-align: center;
  min-width: 200px;
}
.platform strong { display: block; font-size: 15px; margin-bottom: 8px; }
.platform code { font-size: 12px; color: var(--text-muted); }

/* Footer */
.footer {
  background: #1a1a2e;
  color: rgba(255,255,255,0.6);
  text-align: center;
  padding: 32px 20px;
  font-size: 13px;
}
.footer a { color: var(--primary); text-decoration: none; }
.footer p { margin-bottom: 4px; }

/* Responsive */
@media (max-width: 640px) {
  .hero-title { font-size: 24px; }
  .hero { padding: 48px 20px; }
  .cards { grid-template-columns: 1fr; }
  .platforms { flex-direction: column; align-items: center; }
}