body {
  background-color: #F5F5F5;
  color: #555;
  font-size: 1.1em;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
}

.container {
  margin: 50px auto;
  max-width: 700px;
}

.element {
  width: 100%;
  height: 250px;
  border: 1px solid black;
  margin: 0 auto;
  background-image: radial-gradient(circle, white, white 10px, black 10px, black);
  background-size: 50px 50px;
}