#particles-js {
   width: 100%;
   height: 100%;
   background-image: url('../images/login_background.png');
   background-size: cover;
   background-position: 50% 50%;
   background-repeat: no-repeat;
   width: 100%;
   height: 100%;
   position: absolute;
   top: 0;
   left: 0;
}