/* Base reset & Variables */
:root {
  --primary-color: #1a73e8;
  --primary-hover: #1557b0;
  --text-primary: #202124;
  --text-secondary: #5f6368;
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --border-color: #dadce0;
  --nav-bg: #ffffff;
  --footer-bg: #f8f9fa;
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --hero-bg: #f8f9fa;
  --success-color: #188038;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-family);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

a:hover {
  text-decoration: underline;
}

ul {
  list-style: none;
}

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 500;
  margin-bottom: 0.5em;
  line-height: 1.2;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; margin-bottom: 1rem;}
h3 { font-size: 1.5rem; }

/* Header & Navigation */
.header {
  background-color: var(--nav-bg);
  box-shadow: 0 1px 2px 0 rgba(60,64,67,0.3), 0 1px 3px 1px rgba(60,64,67,0.15);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  height: 64px;
}

.logo-area {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--text-primary);
}

.logo-area svg {
  width: 32px;
  height: 32px;
}

.nav-links {
  display: flex;
  gap: 30px;
}

.nav-links a {
  color: var(--text-secondary);
  font-weight: 500;
  padding: 8px 12px;
  border-radius: 4px;
  transition: all 0.2s ease;
  text-decoration: none;
}

.nav-links a:hover {
  background-color: rgba(60,64,67,0.08);
  color: var(--text-primary);
}

.nav-links a.active {
  color: var(--primary-color);
  background-color: #e8f0fe;
}

/* Buttons */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: var(--primary-color);
  color: #fff;
  border: none;
  padding: 12px 24px;
  font-size: 1rem;
  font-weight: 500;
  border-radius: 4px;
  cursor: pointer;
  transition: background-color 0.2s;
}

.btn-primary:hover:not([disabled]) {
  background-color: var(--primary-hover);
  text-decoration: none;
}

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

.btn-outline {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: transparent;
  color: var(--primary-color);
  border: 1px solid var(--border-color);
  padding: 12px 24px;
  font-size: 1rem;
  font-weight: 500;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-outline:hover:not([disabled]) {
  background-color: #f8f9fa;
  border-color: #d5d5d5;
}

/* Layout Blocks */
.section {
  padding: 80px 20px;
}

.section-bg {
  background-color: var(--bg-secondary);
}

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

/* Hero Section */
.hero {
  text-align: center;
  padding: 100px 20px 80px;
}

.hero h1 {
  font-size: 3.5rem;
  max-width: 800px;
  margin: 0 auto 24px;
  letter-spacing: -0.5px;
}

.hero p.subtitle {
  font-size: 1.25rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 40px;
}

/* Features Grid */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 40px;
  margin-top: 60px;
}

.feature-card {
  background: #fff;
  padding: 40px 30px;
  border-radius: 12px;
  box-shadow: 0 4px 6px rgba(0,0,0,0.05);
  text-align: left;
  transition: transform 0.2s;
  border: 1px solid var(--border-color);
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 20px rgba(0,0,0,0.08);
}

.feature-icon {
  width: 48px;
  height: 48px;
  margin-bottom: 24px;
  color: var(--primary-color);
}

/* Detail Sections */
.detail-row {
  display: flex;
  align-items: center;
  gap: 60px;
  margin-bottom: 100px;
}

.detail-row:nth-child(even) {
  flex-direction: row-reverse;
}

.detail-content {
  flex: 1;
}

.detail-image {
  flex: 1;
  background: var(--bg-secondary);
  border-radius: 16px;
  min-height: 300px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border-color);
  padding: 40px;
}

.detail-image svg {
  width: 100%;
  max-width: 300px;
  height: auto;
  color: var(--primary-color);
  opacity: 0.8;
}

/* Reviews */
.reviews-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
  margin-top: 50px;
}

.review-card {
  background: #fff;
  padding: 30px;
  border-radius: 8px;
  border: 1px solid var(--border-color);
}

.review-stars {
  color: #fbbc04;
  margin-bottom: 15px;
}

.review-text {
  font-style: italic;
  margin-bottom: 20px;
  color: var(--text-secondary);
}

.review-author {
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 10px;
}

/* Comparison Table */
.compare-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 40px;
  background: #fff;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.compare-table th, .compare-table td {
  padding: 20px;
  text-align: center;
  border: 1px solid var(--border-color);
}

.compare-table th:first-child, .compare-table td:first-child {
  text-align: left;
  font-weight: 500;
}

.compare-table th {
  background: var(--bg-secondary);
}

/* FAQ */
.faq-list {
  max-width: 800px;
  margin: 50px auto 0;
}

.faq-item {
  border-bottom: 1px solid var(--border-color);
  padding: 24px 0;
}

.faq-q {
  font-size: 1.25rem;
  font-weight: 500;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.faq-a {
  color: var(--text-secondary);
}

/* Stats */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 30px;
  text-align: center;
  margin-top: 50px;
}

.stat-item h4 {
  font-size: 3rem;
  color: var(--primary-color);
  margin-bottom: 10px;
}

/* Platform Downloads */
.platforms-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 30px;
  margin-top: 40px;
}

.platform-card {
  padding: 30px;
  text-align: center;
  background: #fff;
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.platform-card svg {
  width: 48px;
  height: 48px;
  margin-bottom: 20px;
  color: var(--text-primary);
}

/* Download Page Specific */
.dl-hero {
  background-color: var(--bg-secondary);
  padding: 60px 20px;
  text-align: center;
  border-bottom: 1px solid var(--border-color);
}

.dl-main-box {
  background: #fff;
  max-width: 600px;
  margin: -40px auto 40px;
  padding: 40px;
  border-radius: 16px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.1);
  position: relative;
  z-index: 10;
  text-align: center;
}

.dl-meta {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-top: 20px;
}

.steps-list {
  margin-top: 30px;
}

.step-item {
  display: flex;
  gap: 20px;
  margin-bottom: 30px;
}

.step-number {
  width: 40px;
  height: 40px;
  background: var(--primary-color);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: bold;
  font-size: 1.2rem;
  flex-shrink: 0;
}

.step-content h4 {
  margin-bottom: 8px;
}

.changelog-list {
  border-left: 2px solid var(--primary-color);
  padding-left: 30px;
  margin-left: 20px;
  margin-top: 40px;
}

.changelog-item {
  position: relative;
  margin-bottom: 40px;
}

.changelog-item::before {
  content: '';
  position: absolute;
  width: 16px;
  height: 16px;
  background: var(--primary-color);
  border-radius: 50%;
  left: -39px;
  top: 4px;
  border: 3px solid #fff;
}

.security-box {
  background: #e6f4ea;
  border: 1px solid #ceead6;
  padding: 20px;
  border-radius: 8px;
  display: flex;
  align-items: flex-start;
  gap: 15px;
  margin-top: 40px;
}

.security-box svg {
  color: var(--success-color);
  width: 24px;
  height: 24px;
  flex-shrink: 0;
}

/* Footer */
.footer {
  background-color: var(--footer-bg);
  padding: 40px 20px;
  text-align: center;
  border-top: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.footer-safe {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--success-color);
  font-weight: 500;
  margin-bottom: 16px;
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 { font-size: 2.5rem; }
  .detail-row, .detail-row:nth-child(even) { flex-direction: column; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .nav-links { gap: 15px; }
  .nav-links a { padding: 8px; }
}

@media (max-width: 480px) {
  .stats-grid { grid-template-columns: 1fr; }
  .hero h1 { font-size: 2rem; }
}