<style>

  div{ 
    border-radius: 20px;
    width: 70%;
    height: 400px;
    margin:  50 auto;
    background: repeating-linear-gradient(
      90deg,
      yellow 0px,
      blue 40px,
      green 40px,
      red 80px
    );
  }

</style>

<div></div>