:root {
  --forest: #1f6b57;
  --forest-dark: #165544;
  --campus: #06C2B3;
  --campus-dark: #049e92;
  --jiajiao: #5c91e9;
  --jiajiao-dark: #3d73d1;
  --text: #1f2937;
  --muted: #6b7280;
  --bg: #f8fafc;
  --card: #ffffff;
  --border: #e5e7eb;
  --brand: var(--forest);
  --brand-dark: var(--forest-dark);
}

.theme-campus { --brand: var(--campus); --brand-dark: var(--campus-dark); }
.theme-jiajiao { --brand: var(--jiajiao); --brand-dark: var(--jiajiao-dark); }

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

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

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

.topnav {
  background: #fff;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 20;
}
.topnav .container {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 20px;
  min-height: 56px;
  padding-top: 10px;
  padding-bottom: 10px;
}
.topnav .logo {
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--forest-dark);
  text-decoration: none;
}
.topnav .logo:hover { text-decoration: none; }
.topnav nav { display: flex; flex-wrap: wrap; gap: 8px 16px; }
.topnav nav a {
  color: var(--text);
  font-size: 0.95rem;
}
.topnav nav a[aria-current="page"] {
  color: var(--brand-dark);
  font-weight: 600;
}

.hero {
  background: linear-gradient(135deg, var(--brand) 0%, var(--brand-dark) 100%);
  color: #fff;
  padding: 48px 0 56px;
}
.hero h1 { font-size: 2rem; margin-bottom: 12px; }
.hero .tagline { font-size: 1.05rem; opacity: 0.95; max-width: 720px; }
.hero .sub { margin-top: 10px; font-size: 1rem; opacity: 0.92; max-width: 720px; }
.hero .en { margin-top: 16px; font-size: 0.92rem; opacity: 0.85; max-width: 720px; }
.hero .kicker {
  font-size: 0.88rem;
  opacity: 0.88;
  margin-bottom: 8px;
  letter-spacing: 0.06em;
}
.hero .note {
  margin-top: 16px;
  display: inline-block;
  background: rgba(255,255,255,0.16);
  border-radius: 8px;
  padding: 8px 12px;
  font-size: 0.9rem;
}
.hero .btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px;
}
.btn {
  display: inline-block;
  padding: 10px 16px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
}
.btn:hover { text-decoration: none; }
.btn-primary {
  background: #fff;
  color: var(--brand-dark);
}
.btn-ghost {
  background: rgba(255,255,255,0.14);
  color: #fff;
  border: 1px solid rgba(255,255,255,0.4);
}
.btn-muted {
  background: rgba(255,255,255,0.18);
  color: #fff;
}

.breadcrumb {
  padding: 16px 0 0;
  font-size: 0.88rem;
  color: var(--muted);
}
.breadcrumb a { color: var(--muted); }
.breadcrumb a:hover { color: var(--brand-dark); }
.breadcrumb .sep { margin: 0 6px; color: #d1d5db; }

.switch-box {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 20px;
  align-items: center;
  justify-content: space-between;
}
.switch-box .go { margin-top: 0; }

section { padding: 48px 0; }
section.hug-top { padding-top: 0; }
section h2 {
  font-size: 1.45rem;
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--brand);
  display: inline-block;
}
.lead { color: var(--muted); margin-bottom: 20px; max-width: 760px; }

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
}
.card h3 { font-size: 1.05rem; margin-bottom: 8px; color: var(--brand-dark); }
.card p, .card li { color: var(--muted); font-size: 0.95rem; }
.card ul { padding-left: 1.15rem; margin-top: 8px; }
.card .soon {
  display: inline-block;
  margin-top: 12px;
  font-size: 0.85rem;
  color: var(--muted);
  background: #f3f4f6;
  border-radius: 999px;
  padding: 4px 10px;
}
.card .go {
  display: inline-block;
  margin-top: 14px;
  font-weight: 600;
  color: var(--brand-dark);
}

.product-card.campus { border-top: 4px solid var(--campus); }
.product-card.jiajiao { border-top: 4px solid var(--jiajiao); }
.product-card h3 { font-size: 1.2rem; }

.features { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; }
.feature-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
}
.feature-card h3 { font-size: 1.05rem; margin-bottom: 8px; color: var(--brand-dark); }
.feature-card p { color: var(--muted); font-size: 0.95rem; }

.screenshots {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
}
.screenshots figure {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  text-align: center;
}
.screenshots img {
  width: 100%;
  max-width: 220px;
  height: auto;
  display: block;
  margin: 0 auto;
  border-radius: 8px;
}
.screenshots figcaption {
  padding: 12px;
  font-size: 0.88rem;
  color: var(--muted);
}

.download-box, .panel {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px;
}
.download-box p, .panel p { margin-bottom: 12px; color: var(--muted); }
.download-box .note, .panel .note {
  margin-top: 16px;
  padding: 14px 16px;
  border-radius: 8px;
  font-size: 0.92rem;
}
.theme-campus .download-box .note { background: #ecfdf5; color: #065f46; }
.theme-jiajiao .panel .note { background: #eff6ff; color: #1e3a8a; }

.steps { counter-reset: step; list-style: none; }
.steps li {
  position: relative;
  padding: 12px 12px 12px 48px;
  margin-bottom: 10px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  color: var(--muted);
}
.steps li::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 14px;
  top: 12px;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--brand);
  color: #fff;
  font-size: 0.85rem;
  font-weight: 700;
  text-align: center;
  line-height: 24px;
}

.faq details {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  margin-bottom: 10px;
  padding: 12px 16px;
}
.faq summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--text);
}
.faq details p { margin-top: 8px; color: var(--muted); font-size: 0.95rem; }

.legal-note {
  color: var(--muted);
  font-size: 0.9rem;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 16px 18px;
}

.doc {
  max-width: 800px;
  margin: 0 auto;
  padding: 32px 20px 48px;
}
.doc h1 { font-size: 1.6rem; margin-bottom: 8px; color: var(--brand-dark); }
.doc .meta { color: var(--muted); font-size: 0.9rem; margin-bottom: 28px; }
.doc h2 { font-size: 1.1rem; margin: 24px 0 10px; }
.doc p, .doc li { font-size: 0.96rem; margin-bottom: 10px; }
.doc ul { padding-left: 1.25rem; }

.site-footer {
  background: #111827;
  color: #d1d5db;
  padding: 32px 0 40px;
  font-size: 0.9rem;
}
.site-footer a { color: #99f6e4; }
.theme-jiajiao .site-footer a { color: #bfdbfe; }
.site-footer .links { margin-bottom: 16px; }
.site-footer .links a { margin-right: 20px; display: inline-block; margin-bottom: 6px; }
.site-footer .copy { color: #9ca3af; line-height: 1.8; }
.site-footer .beian { margin-top: 8px; font-size: 0.88rem; }

@media (max-width: 640px) {
  .hero { padding: 36px 0 40px; }
  .hero h1 { font-size: 1.55rem; }
  section { padding: 36px 0; }
  .topnav nav { width: 100%; }
}