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

.main {
    width: 800px;
    min-height: 100vh;
    margin: 0 auto;
    padding: 20px;
    background-color: #f5f5f5;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}
 /* 媒体查询，小于800px时，宽度自适应 */
 @media (max-width: 800px) {
    .main {
        width: 100%;
    }
}

.mt10 {
    margin-top: 10px;
}

.mt {
    margin-top: 10px;
}

.content-section {
    margin-top: 30px;
    padding: 20px;
}

.content-section section {
    margin-bottom: 30px;
}

.content-section h2 {
    color: #000000;
    margin-bottom: 15px;
    font-size: 24px;
}

.content-section h3 {
    color: #000000;
    margin: 20px 0 10px;
    font-size: 20px;
}

.content-section h4 {
    color: #000000;
    margin: 15px 0 8px;
    font-size: 18px;
}

.content-section p {
    line-height: 1.6;
    margin-bottom: 15px;
    color: #333;
}

.content-section ul {
    margin-left: 20px;
    margin-bottom: 15px;
}

.content-section li {
    margin-bottom: 8px;
    line-height: 1.5;
}

.content-section strong {
    color: #000000;
}

@media (max-width: 600px) {
    .content-section {
        padding: 15px;
    }
    
    .content-section h2 {
        font-size: 22px;
    }
    
    .content-section h3 {
        font-size: 18px;
    }
}