loader.css

#loader {
  position: absolute;
  left: 50%;
  top: 50%;
  z-index: 1;
  width: 150px;
  height: 150px;
  margin: -75px 0 0 -75px;
  border: 16px solid #f3f3f3;
  border-radius: 50%;
  border-top: 16px solid #3498db;
  border-bottom: 16px solid #3498db;
  border-top: 16px solid #3498db;
  width: 120px;
  height: 120px;
  -webkit-animation: spin 0.1s linear infinite;
  animation: spin 1s linear infinite;
}

@-webkit-keyframes spin {
  0% { -webkit-transform: rotate(0deg); }
  100% { -webkit-transform: rotate(360deg); }
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Add animation to "page content" */
.animate-bottom {
  position: relative;
  -webkit-animation-name: animatebottom;
  -webkit-animation-duration: 0.1s;
  animation-name: animatebottom;
  animation-duration: 0.1s;
}

@-webkit-keyframes animatebottom {
  from { bottom:-100px; opacity:0 } 
  to { bottom:0px; opacity:1 }
}

@keyframes animatebottom { 
  from{ bottom:-100px; opacity:0 } 
  to{ bottom:0; opacity:1 }
}

#myDiv {
  display: none;
  text-align: center;
}