Edit in JSFiddle

.stars {
  position: absolute;
  width: 100%;
  height: 100%;
  background-image: url("data:image/svg+xml;utf-8,\
    <svg width='300px' height='300px' viewBox='0 0 300 300' xmlns='http://www.w3.org/2000/svg'>\
      <g stroke-width='2' stroke='rgb(246,166,35)' fill='rgb(248,232,28)'>\
        <polygon points='150 205 85.3436222 238.991869 97.6918916 166.995935 45.3837832 116.008131 117.671811 105.504065 150 40 182.328189 105.504065 254.616217 116.008131 202.308108 166.995935 214.656378 238.991869'></polygon>\
      </g>\
    </svg>");
  background-color: #003366;
  background-size: 50px;
}

<div class="stars"></div>