section.timeline {
    padding: 100px 5%;
  }
  
  /* Qin: 一开始先控制其不可见 */
  #timeline{
    visibility:hidden; 
  }

  .timeline {
    position: relative;
  }
  .timeline::before {
    content: "";
    background: #d7d7d7;
    width: 5px;
    height: 86%;
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
  }
  
  .timeline-item {
    width: 100%;
    margin-bottom: 70px;
  }
  .timeline-item:nth-child(even) .timeline-content {
    float: right;
    padding: 40px 30px 10px 30px;
  }
  .timeline-item:nth-child(even) .timeline-content .date {
    right: auto;
    left: 0;
  }
  .timeline-item:nth-child(even) .timeline-content::after {
    content: "";
    position: absolute;
    border-style: solid;
    width: 0;
    height: 0;
    top: 30px;
    left: -15px;
    border-width: 10px 15px 10px 0;
    border-color: transparent #f5f5f5 transparent transparent;
  }
  .timeline-item::after {
    content: "";
    display: block;
    clear: both;
  }
  
  .timeline-content {
    position: relative;
    width: 45%;
    padding: 15px 30px;
    border-radius: 4px;
    background: #f5f5f5;
    box-shadow: 0 20px 25px -15px rgba(0, 0, 0, 0.3);
  }
  .timeline-content::after {
    content: "";
    position: absolute;
    border-style: solid;
    width: 0;
    height: 0;
    top: 30px;
    right: -15px;
    border-width: 10px 0 10px 15px;
    border-color: transparent transparent transparent #f5f5f5;
  }
  
  .timeline-img {
    width: 30px;
    height: 30px;
    background: #ffffff;
    border-radius: 50%;
    position: absolute;
    left: 50%;
    margin-top: 25px;
    margin-left: -15px;
  }
  
  a.atimeline {
    background: #3399ff;
    color: #FFFFFF;
    padding: 8px 20px;
    text-transform: uppercase;
    font-size: 14px;
    margin-bottom: 12px;
    margin-top: 6px;
    display: inline-block;
    border-radius: 2px;
    box-shadow: 0 1px 3px -1px rgba(0, 0, 0, 0.6);
  }
  a:hover, a:active, a:focus {
    background: #2d82d7;
    color: #FFFFFF;
    text-decoration: none;
  }
  
  .timeline-card {
    padding: 0 !important;
  }
  .timeline-card p {
    padding: 0 20px;
    padding-bottom: 6px;
  }
  .timeline-card a {
    margin-left: 20px;
  }
  
  .timeline-item .timeline-img-header {

    background-size: cover;
  }

.timeline-item .timeline-img-header.ali{
  background: linear-gradient(rgba(0, 0, 0, 0), rgba(0, 0, 0, 0.4)), url("../images/TLali.png") center center no-repeat;
}
.timeline-item .timeline-img-header.wp{
  background: linear-gradient(rgba(0, 0, 0, 0), rgba(0, 0, 0, 0.4)), url("../images/TLwp.jpg") center center no-repeat;
}
.timeline-item .timeline-img-header.hexo{
  background: linear-gradient(rgba(0, 0, 0, 0), rgba(0, 0, 0, 0.4)), url("../images/TLhexo.png") center center no-repeat;
}
  
  .timeline-img-header {
    height: 200px;
    position: relative;
    margin-bottom: 20px;
  }
  .timeline-img-header h2 {
    color: #FFFFFF;
    position: absolute;
    bottom: 5px;
    left: 20px;
  }
  
  blockquote {
    margin-top: 10px;
    /* margin-bottom: 18px; */
    color: #757575;
    border-left-color: #3F51B5;
    padding: 0 20px;
  }
  
  .date {
    background: #669900;
    display: inline-block;
    color: #FFFFFF;
    padding: 10px;
    position: absolute;
    top: 0;
    right: 0;
  }
  
  @media screen and (max-width: 768px) {
    .timeline::before {
      left: 50px;
    }
    .timeline .timeline-img {
      left: 50px;
    }
    .timeline .timeline-content {
      max-width: 100%;
      width: auto;
      margin-left: 70px;
    }
    .timeline .timeline-item:nth-child(even) .timeline-content {
      float: none;
    }
    .timeline .timeline-item:nth-child(odd) .timeline-content::after {
      content: "";
      position: absolute;
      border-style: solid;
      width: 0;
      height: 0;
      top: 30px;
      left: -15px;
      border-width: 10px 15px 10px 0;
      border-color: transparent #f5f5f5 transparent transparent;
    }
  }