/* === Site 1: Tech Blue - Modern Corporate === */
:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #dbeafe;
  --secondary: #64748b;
  --text: #1e293b;
  --text-light: #64748b;
  --bg: #ffffff;
  --bg-alt: #f8fafc;
  --bg-dark: #0f172a;
  --border: #e2e8f0;
  --success: #10b981;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-lg: 0 10px 40px rgba(0,0,0,0.1);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  line-height: 1.6;
  background: var(--bg);
}

.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* Header & Nav */
.header {
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo { display: flex; align-items: center; gap: 10px; font-size: 1.25rem; font-weight: 700; color: var(--primary); text-decoration: none; }
.logo svg { width: 32px; height: 32px; }
.nav-links { display: flex; gap: 4px; list-style: none; }
.nav-links a {
  display: block;
  padding: 8px 18px;
  border-radius: var(--radius);
  text-decoration: none;
  color: var(--text-light);
  font-size: 0.9375rem;
  font-weight: 500;
  transition: all 0.2s;
}
.nav-links a:hover { background: var(--primary-light); color: var(--primary); }
.nav-links a.active { background: var(--primary); color: #fff; }

/* Hero */
.hero {
  background: linear-gradient(135deg, var(--bg) 0%, var(--primary-light) 100%);
  padding: 80px 0 100px;
  text-align: center;
}
.hero h1 { font-size: 3rem; font-weight: 800; margin-bottom: 16px; color: var(--text); line-height: 1.2; }
.hero .subtitle { font-size: 1.25rem; color: var(--text-light); max-width: 640px; margin: 0 auto 36px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 36px; border-radius: var(--radius);
  font-size: 1rem; font-weight: 600; cursor: pointer;
  border: none; transition: all 0.2s; text-decoration: none;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-1px); box-shadow: var(--shadow-lg); }
.btn-secondary { background: #fff; color: var(--primary); border: 2px solid var(--primary); }
.btn-secondary:hover { background: var(--primary-light); }

/* Section */
.section { padding: 80px 0; }
.section-alt { background: var(--bg-alt); }
.section-title { font-size: 2.25rem; font-weight: 700; text-align: center; margin-bottom: 12px; }
.section-desc { text-align: center; color: var(--text-light); font-size: 1.0625rem; margin-bottom: 56px; max-width: 600px; margin-left: auto; margin-right: auto; }

/* Feature Cards */
.features-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(340px, 1fr)); gap: 24px; }
.feature-card {
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 32px; transition: all 0.2s;
}
.feature-card:hover { box-shadow: var(--shadow-lg); transform: translateY(-3px); border-color: var(--primary-light); }
.feature-icon { width: 48px; height: 48px; margin-bottom: 16px; color: var(--primary); }
.feature-card h3 { font-size: 1.125rem; font-weight: 600; margin-bottom: 10px; }
.feature-card p { color: var(--text-light); font-size: 0.9375rem; line-height: 1.7; }

/* Download Platforms */
.platform-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 20px; }
.platform-card {
  background: var(--bg); border: 2px solid var(--border); border-radius: var(--radius);
  padding: 28px; text-align: center; transition: all 0.2s;
}
.platform-card:hover { border-color: var(--primary); }
.platform-card svg { width: 48px; height: 48px; margin-bottom: 12px; color: var(--primary); }
.platform-card h4 { font-size: 1.0625rem; font-weight: 600; margin-bottom: 6px; }
.platform-card p { font-size: 0.875rem; color: var(--text-light); margin-bottom: 16px; }

/* Details */
.detail-row { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center; margin-bottom: 64px; }
.detail-row.reverse { direction: rtl; }
.detail-row.reverse > * { direction: ltr; }
.detail-content h3 { font-size: 1.5rem; font-weight: 700; margin-bottom: 16px; }
.detail-content p { color: var(--text-light); line-height: 1.8; margin-bottom: 12px; }
.detail-visual {
  background: linear-gradient(135deg, var(--primary-light), #dbeafe);
  border-radius: 16px; height: 280px; display: flex; align-items: center; justify-content: center;
}
.detail-visual svg { width: 120px; height: 120px; color: var(--primary); opacity: 0.5; }

/* Reviews */
.review-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 20px; }
.review-card {
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 28px;
}
.review-stars { color: #f59e0b; margin-bottom: 12px; font-size: 1.125rem; }
.review-card p { color: var(--text); line-height: 1.7; margin-bottom: 16px; font-size: 0.9375rem; }
.review-author { font-weight: 600; font-size: 0.875rem; color: var(--text-light); }

/* Stats */
.stats-bar {
  background: var(--bg-dark); color: #fff; padding: 60px 0;
}
.stats-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 40px; text-align: center; }
.stat-num { font-size: 2.5rem; font-weight: 800; color: #60a5fa; }
.stat-label { font-size: 0.9375rem; color: #94a3b8; margin-top: 4px; }

/* Comparison Table */
.compare-table { width: 100%; border-collapse: collapse; margin-top: 24px; }
.compare-table th, .compare-table td { padding: 16px 20px; text-align: left; border-bottom: 1px solid var(--border); }
.compare-table th { background: var(--primary); color: #fff; font-weight: 600; }
.compare-table tr:nth-child(even) { background: var(--bg-alt); }
.check { color: var(--success); font-weight: 700; }
.cross { color: #ef4444; }

/* FAQ */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item { border-bottom: 1px solid var(--border); }
.faq-q {
  display: flex; justify-content: space-between; align-items: center;
  padding: 24px 0; cursor: pointer; font-weight: 600; font-size: 1.0625rem;
  background: none; border: none; width: 100%; text-align: left; color: var(--text);
}
.faq-q svg { width: 20px; height: 20px; color: var(--primary); transition: transform 0.2s; flex-shrink: 0; }
.faq-item.active .faq-q svg { transform: rotate(180deg); }
.faq-a {
  max-height: 0; overflow: hidden; transition: max-height 0.3s ease;
}
.faq-item.active .faq-a { max-height: 500px; }
.faq-a-inner { padding-bottom: 24px; color: var(--text-light); line-height: 1.8; }

/* Download Page */
.download-hero { background: linear-gradient(135deg, var(--bg-dark) 0%, #1e293b 100%); color: #fff; padding: 80px 0; text-align: center; }
.download-hero h1 { font-size: 2.5rem; margin-bottom: 16px; }
.download-hero p { color: #94a3b8; margin-bottom: 32px; }
.version-badge { display: inline-flex; gap: 24px; justify-content: center; margin-bottom: 24px; flex-wrap: wrap; }
.version-badge span { background: rgba(255,255,255,0.1); padding: 6px 16px; border-radius: 20px; font-size: 0.875rem; }
.platform-downloads { padding: 60px 0; }
.install-guide { background: var(--bg-alt); padding: 60px 0; }
.guide-steps { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 24px; counter-reset: step; }
.guide-step { position: relative; padding-left: 48px; }
.guide-step::before { counter-increment: step; content: counter(step); position: absolute; left: 0; top: 0; width: 36px; height: 36px; background: var(--primary); color: #fff; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-weight: 700; }
.guide-step h4 { font-weight: 600; margin-bottom: 8px; }
.guide-step p { font-size: 0.9375rem; color: var(--text-light); line-height: 1.7; }
.sys-reqs { padding: 60px 0; }
.reqs-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 20px; }
.reqs-card { border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; }
.reqs-card h4 { font-weight: 600; margin-bottom: 12px; display: flex; align-items: center; gap: 8px; }
.reqs-card h4 svg { width: 20px; height: 20px; color: var(--primary); }
.reqs-card ul { list-style: none; font-size: 0.9375rem; color: var(--text-light); line-height: 2; }
.changelog { background: var(--bg-alt); padding: 60px 0; }
.changelog-item { padding: 24px 0; border-bottom: 1px solid var(--border); }
.changelog-item h4 { font-weight: 600; margin-bottom: 8px; }
.changelog-item .version-meta { color: var(--text-light); font-size: 0.875rem; margin-bottom: 12px; }
.changelog-item ul { margin-left: 20px; color: var(--text-light); line-height: 1.9; }

/* zh-cn page article */
.article { max-width: 860px; margin: 0 auto; padding: 60px 24px; }
.article h2 { font-size: 1.75rem; font-weight: 700; margin: 40px 0 20px; }
.article h3 { font-size: 1.25rem; font-weight: 600; margin: 28px 0 12px; }
.article p { line-height: 1.9; margin-bottom: 16px; color: var(--text); }
.article ul, .article ol { margin: 0 0 20px 24px; line-height: 1.9; }
.article li { margin-bottom: 8px; }
.cta-box { background: linear-gradient(135deg, var(--primary-light), #dbeafe); border-radius: 16px; padding: 48px; text-align: center; margin: 48px 0; }
.cta-box h3 { font-size: 1.5rem; margin-bottom: 12px; }
.cta-box p { margin-bottom: 24px; }

/* Footer */
.footer { background: var(--bg-dark); color: #94a3b8; padding: 40px 0; text-align: center; font-size: 0.875rem; }
.footer p { margin-bottom: 6px; }

/* Animations */
@keyframes spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }

/* Responsive */
@media (max-width: 768px) {
  .hero h1 { font-size: 2rem; }
  .detail-row { grid-template-columns: 1fr; gap: 32px; }
  .detail-row.reverse { direction: ltr; }
  .features-grid { grid-template-columns: 1fr; }
  .nav-links { gap: 2px; }
  .nav-links a { padding: 6px 12px; font-size: 0.875rem; }
}