/* 全局样式 */
body {
  margin: 0;
  padding: 0;
  min-height: 100vh;
}

/* 响应式增强 */
@media (max-width: 768px) {
  main {
    padding: 1rem 0.5rem !important;
  }

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

  section {
    padding: 1rem !important;
  }
}

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

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

/* 返回顶部按钮 */
#backToTop {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: #1976d2;
  color: #fff;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  display: none;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(0,0,0,0.3);
  transition: all 0.3s;
  z-index: 999;
}

#backToTop:hover {
  background: #1565c0;
  transform: translateY(-5px);
}

/* UI风格变体 */
.ui-style-1 { --primary-color: #e91e63; }
.ui-style-2 { --primary-color: #9c27b0; }
.ui-style-3 { --primary-color: #3f51b5; }
.ui-style-4 { --primary-color: #00bcd4; }
.ui-style-5 { --primary-color: #4caf50; }
.ui-style-6 { --primary-color: #ff9800; }
.ui-style-7 { --primary-color: #795548; }