SOURCE

<div class="father-box">
    <div class="box">续费￥8.8></div>
</div>

.box{
    background: #7a7a7a;
    color: #fff;
    border-radius: 10px;
    padding: 0 10px;
    width: fit-content;
    position: relative;
    overflow: hidden;
}

.box::after{
    position: absolute;
    content: "";
    height: 100%;
    width: 0px;
    background: #fff;
    left: 0;
    box-shadow: 0 0 5px 3px #fff;
    animation-name: buling;
    animation-delay: 0;
    animation-duration: 2s;
    animation-iteration-count: infinite;
    animation-timing-function: linear;
}

@keyframes buling{
     0%{
         opacity: 0;
        left: 0;
     }
     70%{
         opacity: 0;
        left: 0;
     }
     71%{
         opacity: 1;
        left: 0;
     }
     100%{
        left: 100%;
     }
}