代码片段：@mediaonlyscreenand(max-width:767px){.main-timeline.timeline{margin-top:0;overflow:hidden;}.main-timeline.timeline:before,.main-timeline.timeline:nth-child(2n):before{box-shadow:none;}.main-timeline.timeline-icon,.main-timeline.timeline:nth-child(2n).timeline-icon{margin-top:-30px;m