#particles-js {
  position: absolute;
  width: 100%;
  height: 100%;
  background-color: #228ae6; /*#7986CB*/
  background-repeat: no-repeat;
  background-size: cover;
  background-position: 50% 50%;
  z-index: -1;
  top: 0;
  left: 0;
  bottom: 0;
}