/* ===== Site 3: Tech Dark - Cyan Accent ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
  --primary: #06b6d4;
  --primary-dark: #0891b2;
  --primary-glow: rgba(6,182,212,0.15);
  --text: #e2e8f0;
  --text-secondary: #94a3b8;
  --bg: #0f172a;
  --bg-card: #1e293b;
  --bg-elevated: #273548;
  --border: #334155;
  --radius: 12px;
  --shadow: 0 4px 20px rgba(0,0,0,0.4);
  --shadow-glow: 0 0 20px rgba(6,182,212,0.15);
}

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: 1.7;
}

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

/* Header - Transparent Gradient */
header {
  background: linear-gradient(180deg, rgba(15,23,42,0.98) 0%, rgba(15,23,42,0.9) 100%);
  backdrop-filter: blur(16px);
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid var(--border);
}

nav {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.logo {
  font-size: 22px;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 10px;
  letter-spacing: 0.5px;
}

.nav-links {
  display: flex;
  gap: 8px;
  list-style: none;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 500;
  padding: 10px 20px;
  border-radius: var(--radius);
  transition: all 0.25s;
  border: 1px solid transparent;
}

.nav-links a:hover {
  color: var(--primary);
  background: var(--primary-glow);
  border-color: rgba(6,182,212,0.2);
}

.nav-links a.active {
  color: var(--primary);
  background: var(--primary-glow);
  border-color: rgba(6,182,212,0.3);
  font-weight: 600;
}

/* Hero - Full Width Background */
.hero-wide {
  background: linear-gradient(135deg, var(--bg) 0%, #162032 50%, var(--bg) 100%);
  border-bottom: 1px solid var(--border);
  position: relative;
  overflow: hidden;
}

.hero-wide::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(6,182,212,0.08) 0%, transparent 70%);
  pointer-events: none;
}

.hero-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 90px 24px 70px;
  display: flex;
  gap: 60px;
  align-items: center;
  position: relative;
}

.hero-inner .content { flex: 1; }

.hero-inner h1 {
  font-size: 48px;
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -0.5px;
}

.hero-inner h1 em {
  color: var(--primary);
  font-style: normal;
}

.hero-inner .subtitle {
  font-size: 18px;
  color: var(--text-secondary);
  margin-bottom: 36px;
  line-height: 1.8;
  max-width: 520px;
}

.hero-inner .visual {
  flex: 0 0 400px;
  height: 280px;
  background: linear-gradient(135deg, var(--bg-card) 0%, var(--bg-elevated) 100%);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-glow);
}

.hero-inner .visual svg { width: 140px; height: 140px; opacity: 0.25; }

/* Buttons */
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: #fff;
  padding: 15px 36px;
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  box-shadow: 0 4px 16px rgba(6,182,212,0.3), var(--shadow-glow);
  transition: all 0.25s;
  text-decoration: none;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(6,182,212,0.4), var(--shadow-glow);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: transparent;
  color: var(--text);
  padding: 14px 28px;
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 500;
  border: 1px solid var(--border);
  cursor: pointer;
  transition: all 0.25s;
  text-decoration: none;
}

.btn-secondary:hover {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--primary-glow);
}

/* Section */
.section {
  padding: 80px 24px;
  max-width: 1200px;
  margin: 0 auto;
}

.section-label {
  display: inline-block;
  color: var(--primary);
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-bottom: 12px;
  padding: 4px 12px;
  background: var(--primary-glow);
  border-radius: 4px;
}

.section h2 {
  font-size: 32px;
  font-weight: 700;
  margin-bottom: 16px;
}

.section > p {
  color: var(--text-secondary);
  font-size: 16px;
  margin-bottom: 48px;
  max-width: 600px;
}

/* Feature Cards - Grid with hover glow */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}

.feature-card {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 36px 28px;
  border: 1px solid var(--border);
  transition: all 0.25s;
  position: relative;
}

.feature-card:hover {
  border-color: rgba(6,182,212,0.3);
  box-shadow: var(--shadow-glow);
  transform: translateY(-2px);
}

.feature-card .icon-box {
  width: 52px;
  height: 52px;
  background: var(--primary-glow);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  border: 1px solid rgba(6,182,212,0.15);
}

.feature-card .icon-box svg { width: 26px; height: 26px; }

.feature-card h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 12px;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.75;
}

/* Platforms - Card Row */
.platform-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
}

.platform-card {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 32px 24px;
  text-align: center;
  border: 1px solid var(--border);
  transition: all 0.25s;
}

.platform-card:hover {
  border-color: rgba(6,182,212,0.3);
  box-shadow: var(--shadow-glow);
}

.platform-card .plat-icon-wrap {
  width: 64px;
  height: 64px;
  margin: 0 auto 20px;
  background: var(--bg-elevated);
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
}

.platform-card h4 { font-size: 17px; font-weight: 600; margin-bottom: 8px; }
.platform-card p { font-size: 13px; color: var(--text-secondary); margin-bottom: 8px; }
.platform-card .plat-ver { font-size: 12px; color: #64748b; margin-bottom: 20px; }

.plat-btn {
  display: inline-block;
  padding: 10px 28px;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.25s;
}

.plat-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(6,182,212,0.3);
}

/* Detail Blocks - Alternating */
.detail-wrap { max-width: 1000px; margin: 0 auto; }

.detail-block {
  display: flex;
  align-items: center;
  gap: 50px;
  padding: 50px 0;
  border-bottom: 1px solid var(--border);
}

.detail-block:last-child { border-bottom: none; }
.detail-block:nth-child(even) { flex-direction: row-reverse; }

.detail-block .db-img {
  flex: 0 0 280px;
  height: 200px;
  background: linear-gradient(135deg, var(--bg-card), var(--bg-elevated));
  border-radius: var(--radius);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
}

.detail-block .db-img svg { width: 80px; height: 80px; opacity: 0.3; }

.detail-block .db-text { flex: 1; }
.detail-block .db-text h3 { font-size: 24px; font-weight: 700; margin-bottom: 14px; color: var(--primary); }
.detail-block .db-text p { color: var(--text-secondary); font-size: 15px; line-height: 1.8; margin-bottom: 10px; }

/* Testimonials - Dark Cards */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 20px;
}

.testi-card {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 32px;
  border: 1px solid var(--border);
  transition: all 0.25s;
}

.testi-card:hover { border-color: rgba(6,182,212,0.25); }

.testi-card .quote {
  color: var(--primary);
  font-size: 36px;
  line-height: 1;
  margin-bottom: 8px;
  font-weight: 700;
}

.testi-card p {
  color: var(--text-secondary);
  font-size: 15px;
  line-height: 1.75;
  margin-bottom: 24px;
}

.testi-author {
  display: flex;
  align-items: center;
  gap: 12px;
}

.testi-avatar {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 700;
  font-size: 15px;
}

.testi-author div h5 { font-size: 14px; font-weight: 600; }
.testi-author div span { font-size: 12px; color: #64748b; }

/* Stats */
.stats-strip {
  background: linear-gradient(135deg, var(--bg-card) 0%, var(--bg-elevated) 100%);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 56px 24px;
}

.stats-grid {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 32px;
  text-align: center;
}

.stat-item h3 {
  font-size: 44px;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 8px;
  text-shadow: 0 0 20px rgba(6,182,212,0.2);
}

.stat-item p { font-size: 14px; color: var(--text-secondary); }

/* Comparison */
.comparison-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-card);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
}

.comparison-table th,
.comparison-table td {
  padding: 18px 24px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  font-size: 15px;
}

.comparison-table th {
  background: var(--bg-elevated);
  color: var(--primary);
  font-weight: 600;
}

.comparison-table tr:last-child td { border-bottom: none; }
.comparison-table .yes { color: #34d399; font-weight: 600; }
.comparison-table .no { color: #f87171; }

/* FAQ */
.faq-list { max-width: 800px; margin: 0 auto; }

.faq-item {
  background: var(--bg-card);
  border-radius: var(--radius);
  margin-bottom: 12px;
  border: 1px solid var(--border);
  overflow: hidden;
  transition: all 0.25s;
}

.faq-item:hover { border-color: rgba(6,182,212,0.2); }

.faq-item summary {
  padding: 22px 28px;
  cursor: pointer;
  font-weight: 600;
  font-size: 15px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  list-style: none;
  color: var(--text);
}

.faq-item summary::-webkit-details-marker { display: none; }

.faq-item summary::after {
  content: '+';
  font-size: 22px;
  color: var(--primary);
  font-weight: 300;
  transition: all 0.2s;
}

.faq-item[open] summary::after { content: '−'; }

.faq-item p {
  padding: 0 28px 22px;
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.85;
}

/* Download Page */
.dl-hero {
  background: linear-gradient(135deg, var(--bg-card) 0%, var(--bg-elevated) 100%);
  border-bottom: 1px solid var(--border);
  padding: 72px 24px;
  text-align: center;
}

.dl-hero h1 { font-size: 42px; font-weight: 800; margin-bottom: 16px; }
.dl-hero > p { color: var(--text-secondary); font-size: 17px; margin-bottom: 40px; }

.dl-main-card {
  background: var(--bg);
  border-radius: var(--radius);
  padding: 40px;
  max-width: 600px;
  margin: 0 auto;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.dl-meta-row {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin: 24px 0;
  font-size: 13px;
  color: var(--text-secondary);
}

.dl-btn-main {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #fff;
  padding: 16px 48px;
  border-radius: var(--radius);
  font-size: 16px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: all 0.25s;
}

.dl-btn-main:hover { transform: translateY(-2px); box-shadow: 0 6px 24px rgba(6,182,212,0.35); }

/* Guide */
.guide-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
}

.guide-card {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 30px 24px;
  border: 1px solid var(--border);
  border-left: 3px solid var(--primary);
}

.guide-card .g-num {
  font-size: 36px;
  font-weight: 800;
  color: var(--primary);
  opacity: 0.4;
  margin-bottom: 12px;
}

.guide-card h4 { font-size: 16px; font-weight: 600; margin-bottom: 10px; }
.guide-card p { color: var(--text-secondary); font-size: 13px; line-height: 1.75; }

/* Requirements */
.req-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.req-card {
  background: var(--bg-card);
  border-radius: var(--radius);
  padding: 24px;
  border: 1px solid var(--border);
}

.req-card h4 { font-size: 15px; font-weight: 700; margin-bottom: 16px; color: var(--primary); }
.req-card ul { list-style: none; }
.req-card li {
  padding: 7px 0;
  font-size: 13px;
  color: var(--text-secondary);
  border-bottom: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
}

.req-card li:last-child { border-bottom: none; }

/* Changelog */
.changelog-list { max-width: 800px; margin: 0 auto; }

.changelog-entry {
  padding: 28px 0;
  border-bottom: 1px solid var(--border);
}

.changelog-entry:last-child { border-bottom: none; }

.cl-tag {
  display: inline-block;
  background: var(--primary-glow);
  color: var(--primary);
  padding: 4px 14px;
  border-radius: 4px;
  font-size: 13px;
  font-weight: 700;
  margin-right: 12px;
}

.cl-date { font-size: 13px; color: #64748b; }

.changelog-entry h4 { font-size: 16px; font-weight: 600; margin: 12px 0 8px; }
.changelog-entry ul { list-style: disc; padding-left: 20px; }
.changelog-entry li { font-size: 13px; color: var(--text-secondary); padding: 3px 0; }

/* SEO Page */
.seo-hero {
  background: linear-gradient(135deg, var(--bg-card) 0%, var(--bg-elevated) 100%);
  border-bottom: 1px solid var(--border);
  padding: 80px 24px;
  text-align: center;
}

.seo-hero h1 {
  font-size: 38px;
  font-weight: 800;
  margin-bottom: 16px;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

.seo-hero p { color: var(--text-secondary); font-size: 17px; max-width: 600px; margin: 0 auto; }

.seo-body {
  max-width: 800px;
  margin: 0 auto;
  padding: 60px 24px;
}

.seo-body h2 {
  font-size: 26px;
  font-weight: 700;
  margin: 48px 0 16px;
  color: var(--primary);
}

.seo-body h3 {
  font-size: 19px;
  font-weight: 600;
  margin: 32px 0 12px;
}

.seo-body p {
  color: var(--text-secondary);
  font-size: 15px;
  line-height: 1.9;
  margin-bottom: 18px;
}

.seo-body ul {
  list-style: disc;
  padding-left: 24px;
  margin-bottom: 18px;
}

.seo-body li { color: var(--text-secondary); font-size: 14px; padding: 5px 0; line-height: 1.7; }
.seo-body strong { color: var(--text); }

.seo-cta {
  text-align: center;
  padding: 56px 32px;
  background: var(--bg-card);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  margin: 56px 0;
}

.seo-cta h3 { font-size: 26px; font-weight: 700; margin-bottom: 12px; }
.seo-cta p { margin-bottom: 28px; }

/* Footer */
footer {
  background: var(--bg-card);
  border-top: 1px solid var(--border);
  padding: 40px 24px;
  text-align: center;
}

.footer-content { max-width: 1200px; margin: 0 auto; }
.footer-content p { font-size: 13px; color: #64748b; line-height: 1.8; }

.footer-safe {
  color: var(--text-secondary);
  font-weight: 500;
  margin-bottom: 8px;
  font-size: 14px;
}

/* Skip link */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--primary);
  color: #fff;
  padding: 8px 16px;
  z-index: 1000;
  text-decoration: none;
  font-size: 13px;
}

.skip-link:focus { top: 0; }

/* Responsive */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .hero-inner { flex-direction: column; padding: 56px 20px; }
  .hero-inner h1 { font-size: 32px; }
  .hero-inner .visual { flex: none; width: 100%; height: 200px; }
  .detail-block, .detail-block:nth-child(even) { flex-direction: column; }
  .detail-block .db-img { flex: none; width: 100%; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .stat-item h3 { font-size: 32px; }
  .section { padding: 56px 20px; }
}