#mainContainer {
  position: relative;
  width: 100%;
  height: 100%;
  display: block;
  
}
#loader {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 100px;
  height: 100px;
  display: block;
  background-color: aliceblue;
}
#content, #adContainer {
  position: absolute;
  top: 0px;
  left: 0px;
  width: auto;
  height: auto;
}

#contentElement {
  width: auto;
  height: auto;
  overflow: hidden;
  display: none;
}


#container {
  position: absolute;
  top: 0;
  left: 0;
  width: 0;
  height: 0;
  overflow: hidden;
  max-width: 100%;
  max-height: 100%;
  min-width: 100%;
  min-height: 100%;
  box-sizing: border-box;
}