.box{
position: relative;
width:180px;
height:250px;
background: rgba(0,0,0,0.8);
border-radius: 20px;
display: flex;
justify-content:center;
align-items: center;
overflow: hidden;
}
.box::before{
content:'';
position:absolute;
width: 100px;
height: 120%;
background:linear-gradient(#ffd900,#f9000c);
animation:lineRoll 3s linear infinite;
}
@keyframes lineRoll{
0%{
transform: rotate(0deg);
}
50%{
transform: rotate(180deg);
}
to{
transform: rotate(360deg);
}
}
.box::after{
content: '';
position: absolute;
background: #795548;
right:4px;
top:4px;
left:4px;
bottom:4px;
border-radius: 20px;
}
.box h2{
text-align: center;
color:white;
font-size:3em;
text-shadow:2px 2px pink;
z-index:1;
}
<div class="box">
<h2>线性流动</h2>
</div>