/* 共用样式 */
body { 
    font-family: Arial, sans-serif; 
    margin: 0; 
    padding: 0; 
}
header { 
    background-color: #4CAF50; 
    color: white; 
    padding: 10px 0; 
    text-align: center; 
}
nav { 
    display: flex; 
    justify-content: center; 
    background-color: #333; 
    flex-wrap: wrap;
}
nav a { 
    color: white; 
    padding: 14px 20px; 
    text-decoration: none; 
    text-align: center; 
}
nav a:hover { 
    background-color: #ddd; 
    color: black; 
}
.container { 
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    margin-bottom: 60px; /* 为固定底部的footer留出空间 */
}
section { 
    margin-bottom: 30px; 
}
.card {
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 15px;
    margin-bottom: 20px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}
img { 
    max-width: 100%; 
    height: auto; 
    margin: 0 auto; 
    display: block; 
}
section h2 { 
    text-align: center; 
    margin-bottom: 20px; 
    color: #4CAF50;
}
footer { 
    background-color: #333; 
    color: white; 
    text-align: center; 
    padding: 10px 0; 
    position: fixed; 
    width: 100%; 
    bottom: 0; 
}
/* 首页样式 */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}
.feature-item {
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 15px;
    text-align: center;
    transition: transform 0.3s;
}
.feature-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}
.feature-item img {
    width: 100px;
    height: 100px;
    margin-bottom: 10px;
}
.feature-item h3 {
    margin: 10px 0;
}
.btn {
    display: inline-block;
    background-color: #4CAF50;
    color: white;
    padding: 8px 16px;
    text-decoration: none;
    border-radius: 4px;
    margin-top: 10px;
}
.btn:hover {
    background-color: #45a049;
}
/* 响应式设计 */
@media (max-width: 768px) {
    nav {
        flex-direction: column;
    }
    .feature-grid {
        grid-template-columns: 1fr;
    }
}