/* 小海豚学习 - 全局样式 */

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

body {
  font-family: 'Microsoft YaHei', '微软雅黑', sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  min-height: 100vh;
  padding: 20px;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
}

/* 头部样式 */
.header {
  text-align: center;
  padding: 40px 20px;
  color: white;
}

.logo {
  font-size: 48px;
  margin-bottom: 10px;
}

.title {
  font-size: 36px;
  font-weight: bold;
  text-shadow: 2px 2px 4px rgba(0,0,0,0.2);
  margin-bottom: 10px;
}

.subtitle {
  font-size: 18px;
  opacity: 0.9;
}

/* 模块卡片 */
.modules {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 30px;
  padding: 40px 20px;
}

.module-card {
  background: white;
  border-radius: 20px;
  padding: 40px 30px;
  text-align: center;
  box-shadow: 0 10px 40px rgba(0,0,0,0.15);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  cursor: pointer;
  text-decoration: none;
  color: inherit;
}

.module-card:hover {
  transform: translateY(-10px);
  box-shadow: 0 20px 60px rgba(0,0,0,0.2);
}

.module-icon {
  font-size: 64px;
  margin-bottom: 20px;
}

.module-title {
  font-size: 28px;
  font-weight: bold;
  color: #333;
  margin-bottom: 10px;
}

.module-desc {
  font-size: 16px;
  color: #666;
}

/* 语文模块 - 绿色主题 */
.module-chinese {
  border-top: 5px solid #4CAF50;
}
.module-chinese .module-icon { color: #4CAF50; }

/* 数学模块 - 蓝色主题 */
.module-math {
  border-top: 5px solid #2196F3;
}
.module-math .module-icon { color: #2196F3; }

/* 英语模块 - 橙色主题 */
.module-english {
  border-top: 5px solid #FF9800;
}
.module-english .module-icon { color: #FF9800; }

/* 返回按钮 */
.back-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,255,255,0.2);
  color: white;
  padding: 12px 24px;
  border-radius: 30px;
  text-decoration: none;
  font-size: 16px;
  margin-bottom: 20px;
  transition: background 0.3s ease;
}

.back-btn:hover {
  background: rgba(255,255,255,0.3);
}

/* 页脚 */
.footer {
  text-align: center;
  padding: 40px 20px;
  color: rgba(255,255,255,0.7);
  font-size: 14px;
}

/* 动画 */
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

.float-animation {
  animation: float 3s ease-in-out infinite;
}

/* 响应式 */
@media (max-width: 768px) {
  .title { font-size: 28px; }
  .module-card { padding: 30px 20px; }
  .module-icon { font-size: 48px; }
  .module-title { font-size: 24px; }
}