* {
  box-sizing: border-box;
}
body {
  margin: 0;
  background: #222;
}

.el {
  width: 100vw;
  height: 100vh;
  padding: 1rem;

  background-image: url(https://images.unsplash.com/photo-1516826049371-1e7856387270?ixlib=rb-1.2.1&q=85&w=1300&fm=jpg&crop=entropy&cs=srgb&ixid=eyJhcHBfaWQiOjE0NTg5fQ);
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;

  mask-image: url(https://s3-us-west-2.amazonaws.com/s.cdpn.io/3/vert-wave.svg);
  mask-size: 100px;
  mask-repeat: repeat-y;
  mask-position: center;
}