技巧四：提升群活跃度与签到率
link.classList.add('active');
.news div{font-size:22px; height:auto; font-weight:bold; font-family:Microsoft YaHei; margin-bottom:2%; margin-left:3%; margin-right:3%; width:94%; padding-top:5%; color:#333; line-height:30px;}
margin-bottom: 2rem;
text-indent: 2em;
float: left;