/* 全局增强样式 */
:root {
  --primary-color: #1890ff;
  --secondary-color: #722ed1;
  --success-color: #52c41a;
  --danger-color: #ff4d4f;
  --text-primary: #333;
  --text-secondary: #666;
  --text-tertiary: #999;
  --bg-light: #f5f5f5;
  --border-color: #e8e8e8;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.12);
  --shadow-lg: 0 8px 20px rgba(0,0,0,0.15);
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
}

html {
  scroll-behavior: smooth;
}

body {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

a {
  transition: color 0.3s ease, background 0.3s ease;
}

button {
  cursor: pointer;
  border: none;
  outline: none;
  transition: all 0.3s ease;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

.btn {
  display: inline-block;
  padding: 10px 24px;
  background: var(--primary-color);
  color: #fff;
  border-radius: var(--radius-sm);
  text-decoration: none;
  font-weight: 500;
  transition: all 0.3s ease;
}

.btn:hover {
  background: #096dd9;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.fade-in {
  animation: fadeIn 0.6s ease-in;
}

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

.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 50px;
  height: 50px;
  background: var(--primary-color);
  color: #fff;
  border-radius: 50%;
  display: none;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  box-shadow: var(--shadow-md);
  cursor: pointer;
  z-index: 999;
  transition: all 0.3s ease;
}

.back-to-top:hover {
  background: #096dd9;
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.back-to-top.show {
  display: flex;
}

@media (max-width: 768px) {
  .back-to-top {
    width: 45px;
    height: 45px;
    bottom: 20px;
    right: 20px;
    font-size: 18px;
  }
}

@media print {
  header, .back-to-top {
    display: none;
  }
  
  body {
    background: #fff;
  }
}