.content-box{
    margin: 20px 20px;
}

.content-box h3{
    color: #333;
    margin-bottom: 20px;
    border-bottom: 3px solid #007bff;   /*为h3 添加一个底部边框*/
}

.content-box .bottom{
    display: flex;
    justify-content: space-between;
    align-items: center;
}