<div></div>

body {
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  width: 100vw;
  min-height: 100vh;
}

div{
  width: 100vw;
  background: linear-gradient(to bottom, sandybrown, chocolate);
  height: 30px;
  position: relative;

    &::before,
    &::after {
      content: "";
      position: absolute;
      left: 0;
      bottom: 0;
      right: 0;
      background-repeat: repeat-x;
    }
  
    &::before{
      height: 10px;
      background-size: 20px 20px;
      background-image: radial-gradient(circle at 10px -5px, transparent 12px, white 13px);
    }
    &::after{
      background-repeat: repeat-x;
      height: 15px;
      background-size: 40px 20px;
      background-image: radial-gradient(circle at 10px 15px, white 12px, transparent 13px);
    }
}

// and hopefully there is no js offcourse :)