/* ===== Set 1: 清爽官方风 - 安全下载中心 ===== */
:root {
  --primary: #1a73e8;
  --primary-dark: #1557b0;
  --primary-light: #e8f0fe;
  --accent: #34a853;
  --text: #202124;
  --text-secondary: #5f6368;
  --text-light: #80868b;
  --bg: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-card: #ffffff;
  --border: #dadce0;
  --border-light: #e8eaed;
  --shadow: 0 1px 2px rgba(60,64,67,0.08), 0 2px 6px rgba(60,64,67,0.06);
  --shadow-hover: 0 4px 12px rgba(60,64,67,0.12);
  --radius: 8px;
  --radius-lg: 12px;
  --max-width: 1200px;
  --nav-height: 64px;
}

*, *::before, *::after { 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;
  -webkit-font-smoothing: antialiased;
}

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

/* ===== Header & Nav ===== */
header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: var(--bg);
  border-bottom: 1px solid var(--border-light);
  height: var(--nav-height);
}
nav {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}
.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text);
  text-decoration: none;
}
.nav-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;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.9375rem;
  font-weight: 500;
  transition: all 0.2s ease;
}
.nav-links a:hover {
  background: var(--primary-light);
  color: var(--primary);
}
.nav-links a.active {
  background: var(--primary);
  color: #fff;
}

/* ===== Main ===== */
main { min-height: calc(100vh - var(--nav-height) - 200px); }
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== Hero ===== */
.hero {
  background: linear-gradient(180deg, var(--primary-light) 0%, var(--bg) 100%);
  padding: 80px 0 60px;
  text-align: center;
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(26,115,232,0.1);
  color: var(--primary);
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 0.8125rem;
  font-weight: 500;
  margin-bottom: 24px;
}
.hero h1 {
  font-size: 3rem;
  font-weight: 700;
  line-height: 1.15;
  margin-bottom: 16px;
  color: var(--text);
}
.hero h1 span { color: var(--primary); }
.hero-subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 640px;
  margin: 0 auto 32px;
  line-height: 1.7;
}
.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
}
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}
.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 2px 8px rgba(26,115,232,0.3);
}
.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-hover);
}
.btn-secondary {
  background: var(--bg);
  color: var(--primary);
  border: 1.5px solid var(--border);
}
.btn-secondary:hover {
  border-color: var(--primary);
  background: var(--primary-light);
}
.hero-meta {
  margin-top: 20px;
  font-size: 0.8125rem;
  color: var(--text-light);
}
.hero-meta span { margin: 0 10px; }

/* ===== Section Common ===== */
.section {
  padding: 72px 0;
}
.section-title {
  font-size: 2rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 12px;
  color: var(--text);
}
.section-desc {
  text-align: center;
  color: var(--text-secondary);
  max-width: 560px;
  margin: 0 auto 48px;
  font-size: 1rem;
  line-height: 1.7;
}
.bg-alt { background: var(--bg-secondary); }

/* ===== Feature Cards ===== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
}
.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 32px;
  transition: all 0.25s ease;
}
.feature-card:hover {
  box-shadow: var(--shadow-hover);
  transform: translateY(-3px);
  border-color: var(--border);
}
.feature-icon {
  width: 48px;
  height: 48px;
  background: var(--primary-light);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}
.feature-icon svg { width: 24px; height: 24px; color: var(--primary); }
.feature-card h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 10px;
}
.feature-card p {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.7;
}

/* ===== Platform Cards ===== */
.platform-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
}
.platform-card {
  background: var(--bg-card);
  border: 1.5px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 28px 20px;
  text-align: center;
  transition: all 0.2s ease;
}
.platform-card:hover {
  border-color: var(--primary);
  box-shadow: var(--shadow-hover);
}
.platform-card .plat-icon {
  width: 56px;
  height: 56px;
  margin: 0 auto 16px;
  background: var(--bg-secondary);
  border-radius: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.platform-card .plat-icon svg { width: 28px; height: 28px; }
.platform-card h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 6px;
}
.platform-card p {
  font-size: 0.8125rem;
  color: var(--text-light);
  margin-bottom: 16px;
}
.platform-card .btn-sm {
  padding: 8px 20px;
  font-size: 0.8125rem;
}

/* ===== Deep Feature ===== */
.deep-feature {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
  margin-bottom: 64px;
}
.deep-feature:last-child { margin-bottom: 0; }
.deep-feature.reverse { direction: rtl; }
.deep-feature.reverse > * { direction: ltr; }
.deep-feature h3 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 16px;
  color: var(--text);
}
.deep-feature p {
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 12px;
}
.deep-visual {
  background: linear-gradient(135deg, var(--primary-light), #d2e3fc);
  border-radius: var(--radius-lg);
  padding: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 280px;
}
.deep-visual svg { width: 120px; height: 120px; opacity: 0.8; }

/* ===== Stats ===== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.stat-item {
  text-align: center;
  padding: 32px 20px;
  background: var(--bg-card);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-light);
}
.stat-number {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--primary);
  line-height: 1;
  margin-bottom: 8px;
}
.stat-label {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

/* ===== Reviews ===== */
.review-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}
.review-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 24px;
}
.review-stars {
  display: flex;
  gap: 3px;
  margin-bottom: 12px;
}
.review-stars svg { width: 16px; height: 16px; color: #fbbc04; }
.review-text {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 16px;
}
.review-author {
  display: flex;
  align-items: center;
  gap: 10px;
}
.review-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--primary-light);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.8125rem;
  color: var(--primary);
}
.review-name { font-weight: 600; font-size: 0.875rem; }

/* ===== Compare Table ===== */
.compare-table-wrap { overflow-x: auto; }
.compare-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9375rem;
}
.compare-table th, .compare-table td {
  padding: 14px 18px;
  text-align: left;
  border-bottom: 1px solid var(--border-light);
}
.compare-table th {
  background: var(--bg-secondary);
  font-weight: 600;
  color: var(--text);
}
.compare-table tr:hover { background: var(--bg-secondary); }
.compare-table td:first-child { font-weight: 500; }
.check { color: var(--accent); font-weight: 600; }
.dash { color: var(--text-light); }

/* ===== Scenarios ===== */
.scenario-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
}
.scenario-card {
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 28px;
  text-align: center;
}
.scenario-icon {
  width: 56px;
  height: 56px;
  background: var(--primary-light);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
}
.scenario-icon svg { width: 26px; height: 26px; color: var(--primary); }
.scenario-card h4 { font-size: 1rem; font-weight: 600; margin-bottom: 8px; }
.scenario-card p { font-size: 0.875rem; color: var(--text-secondary); line-height: 1.6; }

/* ===== FAQ ===== */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  border-bottom: 1px solid var(--border-light);
  padding: 24px 0;
}
.faq-item h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 10px;
  color: var(--text);
}
.faq-item p {
  color: var(--text-secondary);
  font-size: 0.9375rem;
  line-height: 1.7;
}

/* ===== Download Page Specific ===== */
.download-hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: #fff;
  padding: 72px 0 56px;
  text-align: center;
}
.download-hero h1 { font-size: 2.5rem; font-weight: 700; margin-bottom: 12px; }
.download-hero p { opacity: 0.9; max-width: 560px; margin: 0 auto 28px; font-size: 1.0625rem; }
.download-hero .btn-primary {
  background: #fff;
  color: var(--primary);
  box-shadow: 0 4px 16px rgba(0,0,0,0.15);
}
.download-hero .btn-primary:hover { background: #f8f9fa; }
.download-meta {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin-top: 20px;
  font-size: 0.8125rem;
  opacity: 0.85;
}

/* Download Cards */
.download-section { padding: 56px 0; }
.download-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}
.download-card {
  background: var(--bg-card);
  border: 1.5px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 32px;
  text-align: center;
}
.download-card h3 { font-size: 1.125rem; font-weight: 600; margin: 14px 0 6px; }
.download-card .plat-ver { font-size: 0.8125rem; color: var(--text-light); margin-bottom: 12px; }
.download-card .plat-req { font-size: 0.8125rem; color: var(--text-secondary); margin-bottom: 20px; line-height: 1.6; }

/* Install Steps */
.steps { display: flex; gap: 16px; counter-reset: step; }
.step-item {
  flex: 1;
  background: var(--bg-card);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: 24px;
  position: relative;
}
.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: 0.875rem;
  margin-bottom: 14px;
}
.step-item h4 { font-size: 0.9375rem; font-weight: 600; margin-bottom: 8px; }
.step-item p { font-size: 0.8125rem; color: var(--text-secondary); line-height: 1.6; }

/* Sys Requirements Table */
.sys-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}
.sys-table th, .sys-table td {
  padding: 12px 16px;
  border: 1px solid var(--border-light);
  text-align: left;
}
.sys-table th { background: var(--bg-secondary); font-weight: 600; }
.sys-table tr:nth-child(even) { background: var(--bg-secondary); }

/* Changelog */
.changelog-item {
  display: flex;
  gap: 20px;
  padding: 20px 0;
  border-bottom: 1px solid var(--border-light);
}
.changelog-ver {
  min-width: 100px;
  font-weight: 700;
  color: var(--primary);
  font-size: 0.9375rem;
}
.changelog-date { color: var(--text-light); font-size: 0.8125rem; margin-bottom: 6px; }
.changelog-note { color: var(--text-secondary); font-size: 0.875rem; line-height: 1.6; }

/* Accordion */
.accordion-item {
  border: 1px solid var(--border-light);
  border-radius: var(--radius);
  margin-bottom: 10px;
  overflow: hidden;
}
.accordion-header {
  width: 100%;
  padding: 16px 20px;
  background: var(--bg-card);
  border: none;
  text-align: left;
  font-size: 0.9375rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text);
}
.accordion-header::after {
  content: '+';
  font-size: 1.25rem;
  color: var(--text-light);
  transition: transform 0.2s;
}
.accordion-header.active::after { content: '−'; }
.accordion-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}
.accordion-body.open { max-height: 500px; }
.accordion-body > div {
  padding: 0 20px 16px;
  color: var(--text-secondary);
  font-size: 0.875rem;
  line-height: 1.7;
}

/* ===== zh-cn Page Specific ===== */
.article { max-width: 860px; margin: 0 auto; }
.article h2 { font-size: 1.75rem; font-weight: 700; margin: 48px 0 20px; color: var(--text); }
.article h3 { font-size: 1.25rem; font-weight: 600; margin: 32px 0 14px; color: var(--text); }
.article p { color: var(--text-secondary); line-height: 1.85; margin-bottom: 16px; font-size: 0.9375rem; }
.article ul, .article ol { margin: 12px 0 20px 24px; color: var(--text-secondary); line-height: 1.8; }
.article li { margin-bottom: 6px; }
.article .highlight-box {
  background: var(--primary-light);
  border-left: 4px solid var(--primary);
  padding: 20px 24px;
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 24px 0;
}
.article .cta-box {
  background: linear-gradient(135deg, var(--primary-light), #d2e3fc);
  border-radius: var(--radius-lg);
  padding: 32px;
  text-align: center;
  margin: 40px 0;
}
.article .cta-box h3 { margin: 0 0 12px; }
.article .cta-box p { margin-bottom: 20px; }
.tip-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin: 24px 0;
}
.tip-card {
  background: var(--bg-secondary);
  border-radius: var(--radius);
  padding: 20px;
}
.tip-card h4 { font-size: 0.9375rem; font-weight: 600; margin-bottom: 8px; }
.tip-card p { font-size: 0.8125rem; margin: 0; }
.shortcut-table { width: 100%; border-collapse: collapse; font-size: 0.875rem; margin: 16px 0; }
.shortcut-table th, .shortcut-table td { padding: 10px 14px; border: 1px solid var(--border-light); text-align: left; }
.shortcut-table th { background: var(--bg-secondary); font-weight: 600; }
.shortcut-table code { background: var(--bg-secondary); padding: 2px 8px; border-radius: 4px; font-size: 0.8125rem; }

/* ===== Footer ===== */
footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-light);
  padding: 40px 0 32px;
  margin-top: 80px;
}
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}
.footer-safe {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.875rem;
  color: var(--text-secondary);
}
.footer-safe svg { width: 18px; height: 18px; color: var(--accent); flex-shrink: 0; }
.footer-copy {
  font-size: 0.8125rem;
  color: var(--text-light);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  :root { --nav-height: 56px; }
  nav { padding: 0 16px; }
  .nav-links a { padding: 6px 12px; font-size: 0.8125rem; }
  .hero { padding: 48px 0 40px; }
  .hero h1 { font-size: 1.875rem; }
  .hero-subtitle { font-size: 1rem; }
  .section { padding: 48px 0; }
  .section-title { font-size: 1.5rem; }
  .deep-feature { grid-template-columns: 1fr; gap: 24px; }
  .deep-feature.reverse { direction: ltr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .stat-number { font-size: 2rem; }
  .steps { flex-direction: column; }
  .footer-inner { flex-direction: column; text-align: center; }
  .article h2 { font-size: 1.375rem; }
}
@media (max-width: 480px) {
  .hero h1 { font-size: 1.5rem; }
  .feature-grid { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: 1fr; }
  .platform-grid { grid-template-columns: 1fr; }
}