/* 全局样式 */
* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
  background: #f5f5f5;
  color: #333;
  line-height: 1.6;
}

a {
  color: #667eea;
  transition: color 0.3s;
}

a:hover {
  color: #764ba2;
}

/* 响应式 */
@media (max-width: 768px) {
  main {
    padding: 1rem !important;
  }

  h1 {
    font-size: 1.5rem !important;
  }

  h2 {
    font-size: 1.2rem !important;
  }
}

/* 动画 */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

main section {
  animation: fadeIn 0.6s ease-out;
}