/* ============================================
   Chrome Browser Download Site - Global Styles
   ============================================ */

/* CSS Variables */
:root {
  --primary: #1a73e8;
  --primary-dark: #1557b0;
  --primary-light: #8ab4f8;
  --secondary: #34a853;
  --accent: #fbbc04;
  --danger: #ea4335;
  --text-primary: #202124;
  --text-secondary: #5f6368;
  --text-muted: #80868b;
  --bg-white: #ffffff;
  --bg-light: #f8f9fa;
  --bg-gray: #f1f3f4;
  --border: #dadce0;
  --shadow-sm: 0 1px 2px 0 rgba(60,64,67,0.3), 0 1px 3px 1px rgba(60,64,67,0.15);
  --shadow-md: 0 4px 8px 0 rgba(60,64,67,0.3), 0 6px 12px 4px rgba(60,64,67,0.15);
  --shadow-lg: 0 8px 16px 0 rgba(60,64,67,0.3), 0 12px 24px 8px rgba(60,64,67,0.15);
  --radius: 8px;
  --radius-lg: 16px;
  --max-width: 1200px;
  --nav-height: 64px;
}

/* Reset & Base */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: var(--text-primary);
  background: var(--bg-white);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--primary-dark);
}

/* Utility */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.text-center { text-align: center; }

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

/* ============================================
   Navigation
   ============================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
  display: flex;
  align-items: center;
}

.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
}

.nav-brand svg {
  width: 32px;
  height: 32px;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
}

.nav-menu a {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border-radius: 100px;
  font-size: 0.9375rem;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all 0.2s;
}

.nav-menu a:hover {
  background: var(--bg-gray);
  color: var(--text-primary);
}

.nav-menu a.active {
  background: var(--primary);
  color: #fff;
}

.nav-menu a.active:hover {
  background: var(--primary-dark);
}

.nav-mobile-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
  position: relative;
  padding: calc(var(--nav-height) + 80px) 0 100px;
  background: linear-gradient(135deg, #0d47a1 0%, #1565c0 40%, #1a73e8 100%);
  color: #fff;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  opacity: 0.15;
  pointer-events: none;
}

.hero-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 720px;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}

.hero .subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  line-height: 1.6;
  opacity: 0.9;
  margin-bottom: 32px;
  max-width: 560px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  align-items: center;
}

/* ============================================
   Buttons
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 100px;
  font-size: 0.9375rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: all 0.2s;
  white-space: nowrap;
}

.btn:disabled {
  opacity: 0.7;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--secondary);
  color: #fff;
  box-shadow: 0 2px 4px rgba(52,168,83,0.3);
}

.btn-primary:hover {
  background: #2d8e47;
  transform: translateY(-1px);
  box-shadow: 0 4px 8px rgba(52,168,83,0.4);
}

.btn-secondary {
  background: rgba(255,255,255,0.15);
  color: #fff;
  border: 1px solid rgba(255,255,255,0.3);
}

.btn-secondary:hover {
  background: rgba(255,255,255,0.25);
}

.btn-outline {
  background: transparent;
  color: var(--primary);
  border: 1px solid var(--border);
}

.btn-outline:hover {
  background: var(--bg-light);
  border-color: var(--primary-light);
}

.btn-lg {
  padding: 16px 36px;
  font-size: 1.0625rem;
}

/* ============================================
   Sections
   ============================================ */
.section {
  padding: 80px 0;
}

.section-alt {
  background: var(--bg-light);
}

.section-header {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 56px;
}

.section-header h2 {
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 700;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.section-header p {
  font-size: 1.0625rem;
  color: var(--text-secondary);
}

/* ============================================
   Feature Cards
   ============================================ */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.feature-card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
  transition: all 0.3s;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.feature-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

.feature-icon svg {
  width: 28px;
  height: 28px;
}

.feature-icon.blue { background: #e8f0fe; color: var(--primary); }
.feature-icon.green { background: #e6f4ea; color: var(--secondary); }
.feature-icon.yellow { background: #fef3e8; color: #b06000; }
.feature-icon.red { background: #fce8e8; color: var(--danger); }
.feature-icon.purple { background: #f3e8fd; color: #7b1fa2; }
.feature-icon.teal { background: #e0f7fa; color: #00838f; }

.feature-card h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.feature-card p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ============================================
   Platform Cards
   ============================================ */
.platforms-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
}

.platform-card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: 28px;
  text-align: center;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
  transition: all 0.3s;
}

.platform-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.platform-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius);
  background: var(--bg-light);
}

.platform-icon svg {
  width: 36px;
  height: 36px;
}

.platform-card h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.platform-card p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

/* ============================================
   Content Blocks
   ============================================ */
.content-block {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
  margin-bottom: 64px;
}

.content-block:last-child {
  margin-bottom: 0;
}

.content-block.reverse {
  direction: rtl;
}

.content-block.reverse > * {
  direction: ltr;
}

.content-block .content-img {
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
}

.content-block .content-img img {
  width: 100%;
  height: auto;
}

.content-block h3 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.content-block p {
  color: var(--text-secondary);
  margin-bottom: 12px;
  font-size: 1rem;
}

/* ============================================
   Testimonials
   ============================================ */
.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
}

.testimonial-card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
}

.testimonial-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.testimonial-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--primary-light));
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 600;
  font-size: 1.125rem;
  flex-shrink: 0;
}

.testimonial-meta h4 {
  font-size: 1rem;
  font-weight: 600;
}

.stars {
  display: flex;
  gap: 2px;
  margin-top: 2px;
}

.stars svg {
  width: 16px;
  height: 16px;
  color: var(--accent);
}

.testimonial-card p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ============================================
   Stats
   ============================================ */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 24px;
}

.stat-card {
  text-align: center;
  padding: 32px 24px;
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
}

.stat-number {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--primary);
  line-height: 1;
  margin-bottom: 8px;
}

.stat-label {
  font-size: 0.9375rem;
  color: var(--text-secondary);
}

/* ============================================
   Comparison Table
   ============================================ */
.comparison-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
}

.comparison-table th,
.comparison-table td {
  padding: 16px 20px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

.comparison-table th {
  background: var(--bg-gray);
  font-weight: 600;
  font-size: 0.9375rem;
}

.comparison-table td {
  font-size: 0.9375rem;
}

.comparison-table .check {
  color: var(--secondary);
  font-weight: 600;
}

.comparison-table .cross {
  color: var(--danger);
}

.comparison-table tr:hover td {
  background: var(--bg-light);
}

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

.faq-item {
  background: var(--bg-white);
  border-radius: var(--radius);
  margin-bottom: 12px;
  border: 1px solid var(--border);
  overflow: hidden;
}

.faq-question {
  width: 100%;
  padding: 20px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  background: none;
  border: none;
  font-size: 1rem;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  color: var(--text-primary);
  transition: background 0.2s;
}

.faq-question:hover {
  background: var(--bg-light);
}

.faq-question svg {
  width: 20px;
  height: 20px;
  color: var(--text-muted);
  transition: transform 0.3s;
  flex-shrink: 0;
}

.faq-item.open .faq-question svg {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease-out;
}

.faq-item.open .faq-answer {
  max-height: 500px;
}

.faq-answer-inner {
  padding: 0 24px 20px;
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ============================================
   Download Sections
   ============================================ */
.download-hero {
  background: linear-gradient(135deg, #0d47a1 0%, #1565c0 50%, #1a73e8 100%);
  color: #fff;
  padding: calc(var(--nav-height) + 60px) 0 60px;
  text-align: center;
}

.download-hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 700;
  margin-bottom: 16px;
}

.download-hero p {
  font-size: 1.0625rem;
  opacity: 0.9;
  margin-bottom: 32px;
}

.download-main-card {
  background: rgba(255,255,255,0.1);
  backdrop-filter: blur(10px);
  border-radius: var(--radius-lg);
  padding: 40px;
  max-width: 480px;
  margin: 0 auto;
  border: 1px solid rgba(255,255,255,0.2);
}

.download-main-card .file-meta {
  display: flex;
  gap: 16px;
  justify-content: center;
  margin-top: 16px;
  font-size: 0.875rem;
  opacity: 0.8;
}

.download-card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
}

.download-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.download-card .version-info {
  font-size: 0.875rem;
  color: var(--text-muted);
  margin-bottom: 16px;
}

.download-card .requirements {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin: 16px 0;
  padding: 12px;
  background: var(--bg-light);
  border-radius: var(--radius);
}

.download-card .requirements strong {
  display: block;
  margin-bottom: 4px;
  color: var(--text-primary);
}

.steps-list {
  counter-reset: step;
  list-style: none;
}

.steps-list li {
  position: relative;
  padding-left: 48px;
  margin-bottom: 20px;
  font-size: 0.9375rem;
  color: var(--text-secondary);
}

.steps-list 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: 0.875rem;
  font-weight: 600;
}

.steps-list li strong {
  display: block;
  color: var(--text-primary);
  margin-bottom: 4px;
}

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

.changelog-item {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 24px;
  padding: 24px 0;
  border-bottom: 1px solid var(--border);
}

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

.changelog-version {
  font-weight: 700;
  color: var(--primary);
  font-size: 1rem;
}

.changelog-date {
  font-size: 0.8125rem;
  color: var(--text-muted);
  margin-top: 4px;
}

.changelog-content h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.changelog-content ul {
  list-style: disc;
  padding-left: 20px;
  font-size: 0.9375rem;
  color: var(--text-secondary);
}

.changelog-content li {
  margin-bottom: 4px;
}

/* ============================================
   System Requirements
   ============================================ */
.requirements-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.requirement-card {
  background: var(--bg-white);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
}

.requirement-card h4 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.requirement-card ul {
  list-style: none;
}

.requirement-card li {
  font-size: 0.875rem;
  color: var(--text-secondary);
  padding: 6px 0;
  border-bottom: 1px solid var(--bg-gray);
  display: flex;
  justify-content: space-between;
}

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

.requirement-card li span:first-child {
  color: var(--text-muted);
}

/* ============================================
   Security Notice
   ============================================ */
.security-notice {
  background: linear-gradient(135deg, #e8f5e9 0%, #c8e6c9 100%);
  border-radius: var(--radius-lg);
  padding: 32px;
  display: flex;
  align-items: flex-start;
  gap: 20px;
}

.security-notice .icon {
  width: 48px;
  height: 48px;
  background: var(--secondary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.security-notice .icon svg {
  width: 24px;
  height: 24px;
  color: #fff;
}

.security-notice h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.security-notice p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ============================================
   CTA Section
   ============================================ */
.cta-section {
  background: linear-gradient(135deg, #0d47a1 0%, #1a73e8 100%);
  color: #fff;
  padding: 80px 0;
  text-align: center;
}

.cta-section h2 {
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 700;
  margin-bottom: 16px;
}

.cta-section p {
  font-size: 1.0625rem;
  opacity: 0.9;
  margin-bottom: 32px;
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
}

/* ============================================
   Footer
   ============================================ */
.footer {
  background: var(--text-primary);
  color: #bdc1c6;
  padding: 40px 0;
}

.footer-content {
  display: flex;
  flex-direction: column;
  gap: 16px;
  align-items: center;
  text-align: center;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  color: #fff;
  font-size: 1.125rem;
}

.footer-brand svg {
  width: 28px;
  height: 28px;
}

.footer-links {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  justify-content: center;
}

.footer-links a {
  color: #bdc1c6;
  font-size: 0.875rem;
}

.footer-links a:hover {
  color: #fff;
}

.footer-legal {
  font-size: 0.8125rem;
  color: #9aa0a6;
  max-width: 680px;
  line-height: 1.6;
}

.footer-legal .verify {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: var(--secondary);
  margin-bottom: 8px;
}

.footer-legal .verify svg {
  width: 16px;
  height: 16px;
}

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

/* ============================================
   Fade In Animation
   ============================================ */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-in {
  animation: fadeInUp 0.6s ease-out forwards;
}

/* ============================================
   Scroll Reveal
   ============================================ */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: all 0.6s ease-out;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 768px) {
  .nav-mobile-toggle {
    display: block;
  }

  .nav-menu {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--bg-white);
    flex-direction: column;
    padding: 16px;
    gap: 4px;
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-md);
    transform: translateY(-100%);
    opacity: 0;
    pointer-events: none;
    transition: all 0.3s;
  }

  .nav-menu.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }

  .nav-menu a {
    width: 100%;
    justify-content: flex-start;
  }

  .content-block {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .content-block.reverse {
    direction: ltr;
  }

  .changelog-item {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .hero-actions {
    justify-content: center;
  }

  .section {
    padding: 60px 0;
  }

  .security-notice {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .features-grid,
  .platforms-grid,
  .stats-grid {
    grid-template-columns: 1fr;
  }

  .container {
    padding: 0 16px;
  }

  .download-main-card {
    padding: 24px;
  }
}