/* 全局样式文件：极简主义设计风格和响应式布局 */
@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@300;400;500;700&display=swap');

/* 设计令牌 */
:root {
  /* 颜色 */
  --color-primary: #000000;
  --color-secondary: #333333;
  --color-tertiary: #666666;
  --color-background: #FFFFFF;
  --color-surface: #F8F8F8;
  --color-border: #E5E5E5;
  --color-overlay: rgba(0, 0, 0, 0.05);
  
  /* 间距 */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 2rem;
  --spacing-lg: 3rem;
  --spacing-xl: 4rem;
  
  /* 字体 */
  --font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.5rem;
  
  /* 圆角 */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 1rem;
  
  /* 阴影 */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  
  /* 过渡 */
  --transition-fast: 150ms ease;
  --transition-normal: 300ms ease;
  --transition-slow: 500ms ease;
}

/* 重置样式 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-family);
  font-weight: 400;
  line-height: 1.6;
  color: var(--color-secondary);
  background-color: var(--color-background);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* 通用组件样式 */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-sm);
}

.nav-container {
  position: fixed;
  top: 0;
  width: 100%;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  z-index: 1000;
  border-bottom: 1px solid var(--color-border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 70px;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-weight: 700;
  font-size: var(--font-size-xl);
  color: var(--color-primary);
  text-decoration: none;
  transition: opacity var(--transition-fast);
}

.logo:hover {
  opacity: 0.8;
}

.logo-icon {
  width: 24px;
  height: 24px;
  fill: currentColor;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: var(--spacing-lg);
}

.nav-link {
  position: relative;
  color: var(--color-secondary);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--transition-fast);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1px;
  background-color: var(--color-primary);
  transition: width var(--transition-normal);
}

.nav-link:hover {
  color: var(--color-primary);
}

.nav-link:hover::after {
  width: 100%;
}

/* 按钮样式 */
.btn {
  display: inline-block;
  padding: var(--spacing-xs) var(--spacing-md);
  color: var(--color-primary);
  background-color: transparent;
  border: 1px solid var(--color-primary);
  border-radius: var(--radius-sm);
  font-weight: 500;
  text-decoration: none;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.btn:hover {
  color: var(--color-background);
  background-color: var(--color-primary);
}

/* 卡片样式 */
.card {
  background-color: var(--color-surface);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: transform var(--transition-normal), box-shadow var(--transition-normal);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.card-image {
  position: relative;
  overflow: hidden;
}

.card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform var(--transition-normal), filter var(--transition-normal);
}

.card:hover .card-image img {
  transform: scale(1.05);
  filter: brightness(1.1);
}

.card-content {
  padding: var(--spacing-md);
}

.card-title {
  font-size: var(--font-size-lg);
  font-weight: 500;
  color: var(--color-primary);
  margin-bottom: var(--spacing-xs);
}

.card-description {
  font-size: var(--font-size-sm);
  color: var(--color-tertiary);
  line-height: 1.5;
}

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

.grid-cols-1 { grid-template-columns: repeat(1, 1fr); }
.grid-cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid-cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-cols-4 { grid-template-columns: repeat(4, 1fr); }

/* Hero 区域 */
.hero {
  height: 100vh;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.hero-image {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: -1;
}

.hero-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.3);
  z-index: -1;
}

.hero-content {
  text-align: center;
  color: white;
  z-index: 1;
}

.hero-title {
  font-size: var(--font-size-4xl);
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.hero-subtitle {
  font-size: var(--font-size-xl);
  font-weight: 300;
  opacity: 0.9;
}

/* 页面布局 */
.page {
  min-height: 100vh;
  padding-top: 70px;
}

.section {
  padding: var(--spacing-xl) 0;
}

.section-title {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  color: var(--color-primary);
  text-align: center;
  margin-bottom: var(--spacing-lg);
}

/* 页脚 */
.footer {
  padding: var(--spacing-lg) 0;
  text-align: center;
  border-top: 1px solid var(--color-border);
  color: var(--color-tertiary);
  font-size: var(--font-size-sm);
}

/* 响应式设计 */
@media (max-width: 768px) {
  :root {
    --font-size-3xl: 1.75rem;
    --font-size-4xl: 2rem;
  }

  .container {
    padding: 0 var(--spacing-xs);
  }

  .nav-menu {
    gap: var(--spacing-md);
    font-size: var(--font-size-sm);
  }

  .grid-cols-3 { grid-template-columns: repeat(2, 1fr); }
  .grid-cols-4 { grid-template-columns: repeat(2, 1fr); }

  .hero-title {
    font-size: var(--font-size-3xl);
  }

  .section {
    padding: var(--spacing-lg) 0;
  }
}

@media (max-width: 480px) {
  .grid-cols-2 { grid-template-columns: repeat(1, 1fr); }
  .grid-cols-3 { grid-template-columns: repeat(1, 1fr); }
  .grid-cols-4 { grid-template-columns: repeat(1, 1fr); }

  .nav {
    height: 60px;
  }

  .page {
    padding-top: 60px;
  }
}

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

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

/* 瀑布流布局 */
.masonry {
  column-count: 3;
  column-gap: var(--spacing-md);
}

.masonry-item {
  break-inside: avoid;
  margin-bottom: var(--spacing-md);
}

@media (max-width: 768px) {
  .masonry {
    column-count: 2;
  }
}

@media (max-width: 480px) {
  .masonry {
    column-count: 1;
  }
}