:root {
  --color-primary: #1a1a1a;
  --color-secondary: #666666;
  --color-background: #fafafa;
  --color-surface: #ffffff;
  --color-accent: #e8e8e8;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 2rem;
  --spacing-lg: 4rem;
  --border-radius: 0.25rem;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
  background-color: var(--color-background);
  color: var(--color-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* 导航样式 */
nav {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: var(--spacing-md) 0;
  border-bottom: 1px solid var(--color-accent);
  margin-bottom: var(--spacing-lg);
}

nav a {
  color: var(--color-primary);
  text-decoration: none;
  margin: 0 var(--spacing-sm);
  padding: var(--spacing-xs) var(--spacing-sm);
  transition: var(--transition);
  position: relative;
}

nav a:hover {
  opacity: 0.7;
}

nav a.active::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--color-primary);
}

/* 主容器 */
main {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* 图片容器 */
.image-container {
  margin-bottom: var(--spacing-lg);
}

.image-container img {
  width: 100%;
  height: auto;
  display: block;
  transition: var(--transition);
}

.image-container img:hover {
  transform: scale(1.02);
}

/* 网格布局 */
.grid {
  display: grid;
  gap: var(--spacing-md);
}

.grid-cols-1 {
  grid-template-columns: 1fr;
}

.grid-cols-2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid-cols-3 {
  grid-template-columns: repeat(3, 1fr);
}

@media (max-width: 768px) {
  .grid-cols-2,
  .grid-cols-3 {
    grid-template-columns: 1fr;
  }
}

/* 英雄区域 */
.hero {
  height: 70vh;
  min-height: 500px;
  position: relative;
  overflow: hidden;
}

.hero img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* 卡片样式 */
.card {
  background-color: var(--color-surface);
  border-radius: var(--border-radius);
  overflow: hidden;
  transition: var(--transition);
}

.card:hover {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

/* 文本样式 */
.title {
  font-size: 2.5rem;
  font-weight: 300;
  margin-bottom: var(--spacing-md);
  text-align: center;
}

.subtitle {
  font-size: 1.25rem;
  color: var(--color-secondary);
  margin-bottom: var(--spacing-lg);
  text-align: center;
}

/* 页脚 */
footer {
  text-align: center;
  padding: var(--spacing-lg) 0;
  margin-top: var(--spacing-lg);
  border-top: 1px solid var(--color-accent);
  color: var(--color-secondary);
  font-size: 0.875rem;
}

/* 动画 */
.fade-in {
  animation: fadeIn 0.8s ease-out;
}

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

/* 响应式设计 */
@media (max-width: 1024px) {
  .title {
    font-size: 2rem;
  }
}

@media (max-width: 768px) {
  main {
    padding: 0 var(--spacing-sm);
  }
  
  .hero {
    height: 50vh;
    min-height: 350px;
  }
}

@media (max-width: 480px) {
  .title {
    font-size: 1.75rem;
  }
  
  nav {
    flex-wrap: wrap;
  }
  
  nav a {
    margin: var(--spacing-xs);
  }
}

/* 加载状态 */
.loading {
  background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
  background-size: 200% 100%;
  animation: loading 1.5s infinite;
}

@keyframes loading {
  0% {
    background-position: 200% 0;
  }
  100% {
    background-position: -200% 0;
  }
}

/* 无障碍 */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* 焦点样式 */
*:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* 打印样式 */
@media print {
  nav,
  footer {
    display: none;
  }
  
  main {
    max-width: none;
    padding: 0;
  }
}