实现效果

HTML代码

<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" version="1.1"><polyline points="10,20 10,40 80,40 80,60" stroke-width="2" stroke-dasharray="10 10" fill="none" stroke="#CCF3FF" stroke-linecap="round"  /><polyline points="10,10 10,40 80,40 80,60" stroke-width="2" stroke-dasharray="10 10" fill="none" stroke="#0487FF" stroke-linecap="round"  />
</svg>

CSS代码

polyline {transition: all 1s linear;animation-duration: 60s;animation-timing-function: linear;animation-iteration-count: infinite;animation-name: flow;
}@keyframes flow {from {stroke-dashoffset: 2000; // 通过这个值来控制流动速度}to {stroke-dashoffset: 0;}
}