/* 星云AI卓越学院 - 主题样式 v2.0 */

:root {
  /* 主色调 - 星云蓝色系 */
  --deep-space: #0A1628;
  --nebula-blue: #1E3A8A;
  --star-blue: #3B82F6;
  --sky-blue: #60A5FA;
  --dawn-blue: #93BBFD;
  
  /* 辅助色 */
  --stardust-purple: #6366F1;
  --aurora-cyan: #06B6D4;
  --nebula-pink: #F472B6;
  --cosmic-green: #10B981;
  
  /* 中性色 - 白天模式 */
  --bg-primary: #FFFFFF;
  --bg-secondary: #F9FAFB;
  --bg-tertiary: #F3F4F6;
  --text-primary: #1F2937;
  --text-secondary: #6B7280;
  --text-tertiary: #9CA3AF;
  --border-color: #E5E7EB;
  
  /* 渐变 */
  --gradient-primary: linear-gradient(135deg, #1E3A8A 0%, #3B82F6 50%, #60A5FA 100%);
  --gradient-vibrant: linear-gradient(135deg, #3B82F6 0%, #6366F1 50%, #06B6D4 100%);
  --gradient-cosmic: linear-gradient(135deg, #0A1628 0%, #1E3A8A 50%, #3B82F6 100%);
  --gradient-aurora: linear-gradient(135deg, #6366F1 0%, #F472B6 50%, #06B6D4 100%);
  
  /* 阴影 */
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.06);
  --shadow-base: 0 4px 20px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 10px 40px rgba(0, 0, 0, 0.12);
  --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.15);
  
  /* 圆角 */
  --radius-sm: 4px;
  --radius-base: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-2xl: 20px;
  --radius-3xl: 24px;
  --radius-full: 9999px;
  
  /* 兼容旧代码 */
  --space-gray: var(--text-primary);
  --stellar-gray: var(--text-secondary);
  --moon-gray: var(--border-color);
  --moonlight: var(--bg-secondary);
}

/* 夜间模式 */
[data-theme="dark"] {
  --bg-primary: #0F172A;
  --bg-secondary: #1E293B;
  --bg-tertiary: #334155;
  --text-primary: #F1F5F9;
  --text-secondary: #CBD5E1;
  --text-tertiary: #94A3B8;
  --border-color: #475569;
  
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.2);
  --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.3);
  --shadow-base: 0 4px 20px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 10px 40px rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.6);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", 
               "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* 导航栏样式 */
.navbar {
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 1000;
  transition: all 0.3s ease;
}

.navbar-inner {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.navbar-brand {
  font-size: 20px;
  font-weight: 700;
  color: var(--star-blue);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 12px;
}

.navbar-logo {
  width: 36px;
  height: 36px;
  background: var(--gradient-vibrant);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 700;
  font-size: 18px;
}

.navbar-menu {
  display: flex;
  align-items: center;
  gap: 32px;
}

.navbar-link {
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.3s ease;
  position: relative;
}

.navbar-link:hover {
  color: var(--star-blue);
}

.navbar-link.active {
  color: var(--star-blue);
}

.navbar-link.active::after {
  content: '';
  position: absolute;
  bottom: -21px;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--star-blue);
  border-radius: var(--radius-full);
}

.navbar-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* 主题切换按钮 */
.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-lg);
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.3s ease;
  font-size: 20px;
}

.theme-toggle:hover {
  background: var(--bg-tertiary);
  transform: scale(1.05);
}

/* 语言切换 */
.lang-toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: all 0.3s ease;
  font-weight: 500;
  color: var(--text-primary);
}

.lang-toggle:hover {
  background: var(--bg-tertiary);
}

/* 按钮基础样式 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 10px 20px;
  border-radius: var(--radius-lg);
  font-weight: 600;
  font-size: 14px;
  transition: all 0.3s ease;
  cursor: pointer;
  border: none;
  text-decoration: none;
}

.btn-primary {
  background: var(--gradient-vibrant);
  color: white;
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-secondary {
  background: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: var(--bg-tertiary);
}

.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
}

.btn-ghost:hover {
  background: var(--bg-secondary);
}

/* 容器 */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
}

/* 卡片 */
.card {
  background: var(--bg-primary);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-base);
  padding: 24px;
  transition: all 0.3s ease;
}

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

/* 课程卡片样式 */
.course-card {
  background: var(--bg-primary);
  border-radius: var(--radius-xl);
  overflow: hidden;
  box-shadow: var(--shadow-base);
  transition: all 0.3s ease;
  cursor: pointer;
  border: 1px solid var(--border-color);
}

.course-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--sky-blue);
}

.course-card-image {
  height: 160px;
  background: var(--gradient-aurora);
  opacity: 0.8;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 48px;
  color: white;
}

.course-card-body {
  padding: 20px;
}

.course-card-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
  line-height: 1.4;
}

.course-card-desc {
  color: var(--text-secondary);
  font-size: 14px;
  line-height: 1.6;
  margin-bottom: 16px;
}

.course-card-meta {
  display: flex;
  gap: 16px;
  font-size: 13px;
  color: var(--text-tertiary);
}

/* 标签样式 */
.tag {
  display: inline-block;
  padding: 4px 12px;
  background: var(--bg-secondary);
  border-radius: var(--radius-full);
  font-size: 12px;
  color: var(--star-blue);
  border: 1px solid var(--border-color);
}

/* 网格布局 */
.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 24px;
}

/* 工具类 */
.text-center { text-align: center; }
.flex { display: flex; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: 8px; }
.gap-4 { gap: 16px; }
.mt-4 { margin-top: 16px; }
.mb-4 { margin-bottom: 16px; }

/* 响应式 */
@media (max-width: 768px) {
  .navbar-menu {
    gap: 16px;
  }
  .navbar-link {
    font-size: 14px;
  }
  .course-grid {
    grid-template-columns: 1fr;
  }
  .navbar-actions {
    gap: 8px;
  }
  .lang-toggle span {
    display: none;
  }
}