/* ===== Set 1: Clean Official Style - Secure Download Center ===== */
:root {
  --primary: #1a73e8;
  --primary-dark: #1557b0;
  --secondary: #34a853;
  --accent: #fbbc04;
  --danger: #ea4335;
  --bg: #ffffff;
  --bg-alt: #f8f9fa;
  --bg-section: #f1f3f4;
  --text: #202124;
  --text-secondary: #5f6368;
  --border: #dadce0;
  --shadow: rgba(60,64,67,0.1);
  --radius: 8px;
  --radius-lg: 16px;
  --max-width: 1200px;
}

* { 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);
  background: var(--bg);
  line-height: 1.6;
}

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

/* Header & Navigation */
header {
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
nav {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 20px;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}
.brand svg { width: 32px; height: 32px; }
.nav-links {
  display: flex;
  list-style: none;
  gap: 4px;
}
.nav-links a {
  display: block;
  padding: 8px 18px;
  border-radius: 20px;
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 14px;
  font-weight: 500;
  transition: all 0.2s;
}
.nav-links a:hover { background: var(--bg-alt); color: var(--text); }
.nav-links a.active { background: var(--primary); color: #fff; }

/* Hero */
.hero {
  background: linear-gradient(180deg, #e8f0fe 0%, var(--bg) 100%);
  padding: 80px 24px 60px;
  text-align: center;
}
.hero-inner { max-width: var(--max-width); margin: 0 auto; }
.hero h1 {
  font-size: 52px;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 16px;
  line-height: 1.15;
}
.hero h1 span { color: var(--primary); }
.hero-sub {
  font-size: 20px;
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto 32px;
}
.hero-meta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 20px;
  margin-bottom: 32px;
  font-size: 14px;
  color: var(--text-secondary);
}
.hero-meta .badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 20px;
  font-size: 13px;
}
.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 36px;
  background: var(--primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.2s;
}
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-1px); box-shadow: 0 4px 12px rgba(26,115,232,0.3); }
.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 28px;
  background: #fff;
  color: var(--primary);
  border: 1.5px solid var(--primary);
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 500;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.2s;
}
.btn-secondary:hover { background: var(--primary); color: #fff; }
.btn-lg { padding: 16px 40px; font-size: 18px; border-radius: var(--radius-lg); }

/* Sections */
section { padding: 60px 24px; }
.section-inner { max-width: var(--max-width); margin: 0 auto; }
.section-title {
  font-size: 36px;
  font-weight: 700;
  text-align: center;
  margin-bottom: 12px;
}
.section-desc {
  text-align: center;
  color: var(--text-secondary);
  font-size: 18px;
  max-width: 600px;
  margin: 0 auto 48px;
}
.bg-alt { background: var(--bg-alt); }
.bg-section { background: var(--bg-section); }

/* Feature Cards */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
}
.feature-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  transition: all 0.2s;
}
.feature-card:hover { box-shadow: 0 4px 20px var(--shadow); transform: translateY(-2px); }
.feature-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}
.feature-icon svg { width: 24px; height: 24px; }
.feature-card h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; }
.feature-card p { font-size: 14px; color: var(--text-secondary); line-height: 1.7; }

/* Platform Cards */
.platform-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
}
.platform-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px 20px;
  text-align: center;
  transition: all 0.2s;
}
.platform-card:hover { border-color: var(--primary); box-shadow: 0 2px 12px var(--shadow); }
.platform-card svg { width: 40px; height: 40px; margin-bottom: 12px; }
.platform-card h4 { font-size: 16px; font-weight: 600; margin-bottom: 4px; }
.platform-card p { font-size: 13px; color: var(--text-secondary); margin-bottom: 16px; }
.platform-card .btn-sm {
  padding: 8px 20px;
  font-size: 13px;
}

/* Deep Feature */
.deep-feature {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
  margin-bottom: 48px;
}
.deep-feature.reverse { direction: rtl; }
.deep-feature.reverse > * { direction: ltr; }
.deep-feature h3 { font-size: 28px; font-weight: 700; margin-bottom: 16px; }
.deep-feature p { color: var(--text-secondary); line-height: 1.8; margin-bottom: 12px; }
.deep-feature .feature-visual {
  background: var(--bg-section);
  border-radius: var(--radius-lg);
  padding: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 240px;
}
.deep-feature .feature-visual svg { width: 120px; height: 120px; }

/* Stats */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.stat-item {
  text-align: center;
  padding: 32px;
  background: #fff;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
}
.stat-number { font-size: 40px; font-weight: 800; color: var(--primary); }
.stat-label { font-size: 14px; color: var(--text-secondary); margin-top: 4px; }

/* Reviews */
.review-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}
.review-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
}
.review-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
}
.review-avatar {
  width: 40px; height: 40px;
  border-radius: 50%;
  background: var(--primary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 600;
  font-size: 16px;
}
.review-meta h4 { font-size: 15px; font-weight: 600; }
.stars { display: flex; gap: 2px; }
.stars svg { width: 14px; height: 14px; fill: var(--accent); }
.review-card p { font-size: 14px; color: var(--text-secondary); line-height: 1.7; }

/* Comparison Table */
.compare-table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
}
.compare-table th, .compare-table td {
  padding: 16px 20px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}
.compare-table th {
  background: var(--bg-section);
  font-weight: 600;
  font-size: 14px;
}
.compare-table td { font-size: 14px; color: var(--text-secondary); }
.compare-table .check { color: var(--secondary); font-weight: 600; }
.compare-table .cross { color: var(--danger); }
.compare-table tr:last-child td { border-bottom: none; }

/* Scenarios */
.scenario-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
}
.scenario-card {
  background: #fff;
  border-radius: var(--radius-lg);
  padding: 28px;
  border: 1px solid var(--border);
}
.scenario-card svg { width: 36px; height: 36px; margin-bottom: 12px; }
.scenario-card h4 { font-size: 16px; font-weight: 600; margin-bottom: 8px; }
.scenario-card p { font-size: 14px; color: var(--text-secondary); line-height: 1.6; }

/* FAQ */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
  overflow: hidden;
}
.faq-question {
  width: 100%;
  padding: 18px 24px;
  background: none;
  border: none;
  font-size: 15px;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text);
}
.faq-question::after {
  content: '+';
  font-size: 20px;
  color: var(--primary);
  transition: transform 0.2s;
}
.faq-item.active .faq-question::after { content: '−'; }
.faq-answer {
  padding: 0 24px 18px;
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
  display: none;
}
.faq-item.active .faq-answer { display: block; }

/* Download Page Specific */
.download-hero {
  background: linear-gradient(135deg, #e8f0fe 0%, #d2e3fc 100%);
  padding: 60px 24px;
  text-align: center;
}
.download-hero h1 { font-size: 42px; font-weight: 800; margin-bottom: 16px; }
.download-meta {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin: 24px 0;
  flex-wrap: wrap;
}
.download-meta-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  background: #fff;
  border-radius: 20px;
  font-size: 14px;
  color: var(--text-secondary);
}
.download-section { padding: 48px 24px; }
.platform-detail-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}
.platform-detail-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
}
.platform-detail-card h3 {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 16px;
}
.platform-detail-card h3 svg { width: 28px; height: 28px; }
.platform-detail-card p { font-size: 14px; color: var(--text-secondary); line-height: 1.7; margin-bottom: 16px; }
.install-steps {
  counter-reset: step;
  list-style: none;
}
.install-steps li {
  position: relative;
  padding-left: 48px;
  margin-bottom: 24px;
  font-size: 15px;
  line-height: 1.7;
}
.install-steps li::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 0;
  top: 0;
  width: 32px;
  height: 32px;
  background: var(--primary);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 700;
}
.requirements-table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  margin-top: 16px;
}
.requirements-table th, .requirements-table td {
  padding: 14px 18px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  font-size: 14px;
}
.requirements-table th { background: var(--bg-section); font-weight: 600; }

.version-log { max-width: 800px; margin: 0 auto; }
.version-item {
  border-left: 3px solid var(--primary);
  padding-left: 24px;
  margin-bottom: 28px;
  position: relative;
}
.version-item::before {
  content: '';
  position: absolute;
  left: -7px;
  top: 4px;
  width: 12px;
  height: 12px;
  background: var(--primary);
  border-radius: 50%;
}
.version-header {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 8px;
}
.version-number { font-size: 18px; font-weight: 700; color: var(--primary); }
.version-date { font-size: 13px; color: var(--text-secondary); }
.version-item ul { list-style: disc; padding-left: 20px; color: var(--text-secondary); font-size: 14px; line-height: 1.8; }

/* CTA Section */
.cta-section {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: #fff;
  text-align: center;
  padding: 60px 24px;
  border-radius: var(--radius-lg);
  margin: 48px auto;
  max-width: var(--max-width);
}
.cta-section h2 { font-size: 32px; font-weight: 700; margin-bottom: 12px; }
.cta-section p { font-size: 18px; opacity: 0.9; margin-bottom: 24px; }
.cta-section .btn-primary { background: #fff; color: var(--primary); }
.cta-section .btn-primary:hover { background: var(--bg-alt); }

/* Footer */
footer {
  background: var(--bg-section);
  border-top: 1px solid var(--border);
  padding: 40px 24px;
  margin-top: 60px;
}
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  text-align: center;
}
.footer-inner p { font-size: 13px; color: var(--text-secondary); margin-bottom: 8px; }
.footer-inner .shield { display: inline-flex; align-items: center; gap: 6px; margin-bottom: 12px; }
.footer-inner .shield svg { width: 18px; height: 18px; }

/* Responsive */
@media (max-width: 768px) {
  .hero h1 { font-size: 32px; }
  .hero-sub { font-size: 16px; }
  .nav-links { gap: 2px; }
  .nav-links a { padding: 6px 12px; font-size: 13px; }
  .deep-feature { grid-template-columns: 1fr; }
  .deep-feature.reverse { direction: ltr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .section-title { font-size: 28px; }
  .download-hero h1 { font-size: 30px; }
}

@media (max-width: 480px) {
  .stats-grid { grid-template-columns: 1fr; }
  .hero { padding: 48px 16px 40px; }
  section { padding: 40px 16px; }
  .feature-grid { grid-template-columns: 1fr; }
  nav { padding: 0 12px; height: 56px; }
  .brand { font-size: 16px; }
  .brand svg { width: 26px; height: 26px; }
}