.tree{width:100%;position:relative;margin:0 auto;height:100vh;overflow:hidden}.treeimg{width:35%;height:100%;position:absolute;top:0;right:0}a{text-decoration:none}a,a:hover{color:#000}ul li{list-style:none;float:left}.helper_content_target{top:40px;transition:left .3s}.helper_content_item,.helper_content_target{position:absolute;left:0;width:100%;height:100%}.helper_content_item{top:70px}.helper_center{overflow:hidden}.helper_center_news_target{width:100%;height:100%;white-space:nowrap;position:absolute;left:0;top:90px;transition:left .3s}.helper_center_news_target .helper_content_item{position:static;white-space:normal;display:inline-block;overflow:hidden}.helper_center_navwrap{position:relative;margin:0 auto;width:600px;border-radius:20px}.helper_center_nav{width:100%;height:40px;line-height:40px}.helper_center_nav_item{position:relative;width:140px;height:100%;cursor:pointer}.helper_nav_link{text-decoration:none;position:absolute;top:0;left:-20px;width:100%;height:100%;font-size:16px;font-weight:500;text-align:center;transition:color .3s;z-index:2}.helper_center_navicon{position:absolute;color:#fff;top:0;left:0;width:200px;height:100%;background:#060606;box-shadow:0 2px 15px 0 rgb(68 93 12.7%);border-radius:20px;transition:left .65s cubic-bezier(.19,1,.22,1)}.helper_center .helper_news{margin-top:0}.tree_nav{text-align:center;width:1200px;position:relative;padding-top:38px}