/* Platform-wide styles */
:root {
  --primary-color: #2563eb;
  --secondary-color: #7c3aed;
  --success-color: #10b981;
  --warning-color: #f59e0b;
  --error-color: #ef4444;
  --text-primary: #1f2937;
  --text-secondary: #6b7280;
  --bg-primary: #ffffff;
  --bg-secondary: #f9fafb;
  --border-color: #e5e7eb;
  --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  color: var(--text-primary);
  background: var(--bg-primary);
  line-height: 1.6;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* Platform Header */
.platform-header {
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  padding: 2rem 0;
}

.platform-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.nav-brand .logo {
  height: 40px;
  width: auto;
}

.platform-nav h1 {
  margin: 0;
  font-size: 1.5rem;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--primary-color);
}

.nav-home {
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 500;
}

.nav-home:hover {
  text-decoration: underline;
}

.platform-title {
  margin: 0;
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
}

.platform-tagline {
  margin: 0.5rem 0 0;
  color: var(--text-secondary);
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: white;
  padding: 4rem 0;
}

.hero h1 {
  font-size: 3rem;
  margin: 0 0 1rem;
}

.hero p {
  font-size: 1.25rem;
  opacity: 0.9;
}

/* Book Grid */
.book-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.book-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: transform 0.2s, box-shadow 0.2s;
}

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

.book-cover {
  height: 200px;
  background: var(--bg-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
}

.book-details {
  padding: 1.5rem;
}

.book-details h3 {
  margin: 0 0 0.5rem;
  color: var(--text-primary);
}

.book-details p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin: 0.5rem 0;
}

.book-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 1rem;
}

.book-link {
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 500;
}

.book-link:hover {
  text-decoration: underline;
}

.coming-soon {
  color: var(--warning-color);
  font-size: 0.9rem;
  font-weight: 500;
}

/* Features Grid */
.platform-features {
  padding: 4rem 0;
  background: var(--bg-secondary);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.feature {
  text-align: center;
}

.feature h3 {
  color: var(--text-primary);
  margin: 1rem 0 0.5rem;
}

.feature p {
  color: var(--text-secondary);
}

/* Footer */
.platform-footer {
  background: var(--text-primary);
  color: white;
  padding: 2rem 0;
  text-align: center;
}

.platform-footer a {
  color: #93c5fd;
  text-decoration: none;
}

.platform-footer a:hover {
  text-decoration: underline;
}

.footer-tagline {
  margin-top: 1rem;
  opacity: 0.8;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: 4px;
  text-decoration: none;
  font-weight: 500;
  transition: all 0.2s;
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--primary-color);
  color: white;
}

.btn-primary:hover {
  background: #1d4ed8;
}

.btn-secondary {
  background: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

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

/* Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2rem;
  }
  
  .hero p {
    font-size: 1rem;
  }
  
  .book-grid {
    grid-template-columns: 1fr;
  }
  
  .features-grid {
    grid-template-columns: 1fr;
  }
}

/* Dark mode support */
@media (prefers-color-scheme: dark) {
  :root {
    --text-primary: #f3f4f6;
    --text-secondary: #9ca3af;
    --bg-primary: #111827;
    --bg-secondary: #1f2937;
    --border-color: #374151;
  }
  
  .book-card {
    background: var(--bg-secondary);
  }
  
  .platform-footer {
    background: #030712;
  }
}