<div class="box">
    <h2>01</h2>
  </div>
  <div class="box">
    <h2>02</h2>
  </div>
  <div class="box">
    <h2>03</h2>
  </div>
  <div class="box">
    <h2>04</h2>
  </div>

*
{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Poppins', sans-serif;
}
body
{
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: #0e1538;
}
.box
{
  position: relative;
  width: 300px;
  height: 400px;
  display: flex;
  justify-content: center;
  align-items: center;
  background: rgba(0,0,0,0.5);
  overflow: hidden;
  border-radius: 20px;
  margin-left:40px;
}
.box:before
{
  content: '';
  position: absolute;
  width: 150px;
  height: 125%;
  background: linear-gradient(315deg,#00ccff,#d400d4);
  animation: animate 4s linear infinite
}
@keyframes animate 
{
  0%
  {
    transform: rotate(0deg);
  }
  100%
  {
    transform: rotate(360deg);
  }
}
.box:after
{
  content: '';
  position: absolute;
  inset : 6px;
  background: #0e1538;
  border-radius: 15px;
  z-index: 2;
}
h2
{
  position: relative;
  z-index: 2;
  font-size: 10em;
  color: #fff;
  z-index: 4;
}