.timeline {
    position: relative;
    max-width: 600px;
    margin: 0 auto;
    padding: 20px 0;
}
/* 中间竖线 */
.timeline::before {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    left: 30px;
    width: 4px;
    background: #4B5320;
}
.timeline-item {
    position: relative;
    padding-left: 60px;
    margin-bottom: 20px;
}
.timeline-item:last-child {
    margin-bottom: 0;
}
/* 圆形节点 */
.timeline-item::before {
    content: "";
    position: absolute;
    top: 0;
    left: 18px;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background:  #4B5320;
    border: 4px solid #fff;
    box-shadow: 0 0 3px rgba(0,0,0,0.3);
}
.timeline-item time {
    font-size: 0.9em;
    color: #999;
}
.timeline-item h3 {
    margin: 5px 0;
    font-size: 1.2em;
    color: #333;
}
.timeline-item p {
    margin: 5px 0 0;
    color: #555;
    line-height: 1.5;
}