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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  color: #333;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

header {
  background: rgba(255, 255, 255, 0.95);
  padding: 30px 0;
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
}

header h1 {
  color: #667eea;
  font-size: 2rem;
  margin-bottom: 5px;
}

header .subtitle {
  color: #666;
  font-size: 1rem;
}

main {
  padding: 40px 20px;
  min-height: calc(100vh - 200px);
}

.materials-section h2 {
  color: white;
  margin-bottom: 25px;
  font-size: 1.5rem;
}

.materials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}

.material-card {
  background: white;
  border-radius: 16px;
  padding: 25px;
  display: flex;
  align-items: center;
  gap: 20px;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.material-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);
}

.material-icon {
  font-size: 3rem;
  width: 70px;
  height: 70px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  border-radius: 12px;
  color: white;
}

.material-info h3 {
  color: #333;
  margin-bottom: 8px;
  font-size: 1.1rem;
}

.material-meta {
  color: #999;
  font-size: 0.85rem;
}

.loading, .empty, .error {
  text-align: center;
  color: white;
  padding: 40px;
  font-size: 1.1rem;
}

.error {
  color: #ff6b6b;
}

footer {
  background: rgba(255, 255, 255, 0.9);
  padding:0;
  text 20px -align: center;
  color: #666;
}

@media (max-width: 600px) {
  header h1 {
    font-size: 1.5rem;
  }
  
  .materials-grid {
    grid-template-columns: 1fr;
  }
}