nik.css

/* Tiny reset thingy */
body,html{margin:0;padding:0;}

.wrapper {
  /* The height needs to be set to a fixed value for the effect to work.
   * 100vh is the full height of the viewport. */
  height: 100vh;
  /* The scaling of the images would add a horizontal scrollbar, so disable x overflow. */
  overflow-x: hidden;
  /* Enable scrolling on the page. */
  overflow-y: auto;
  /* Set the perspective to 2px. This is essentailly the simulated distance from the viewport to transformed objects.*/
  perspective: 2px;
}

.section {
 font-family: 'Rock Salt', cursive;
font-size: 250%;

  /* Needed for children to be absolutely positioned relative to the parent. */
  position: relative;
  /* The height of the container. Must be set, but it doesn't really matter what the value is. */
  height: 100vh;
  
  /* For text formatting. */
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  text-shadow: 0 0 0.5px #000;
}

.parallax::after {
  /* Display and position the pseudo-element */
  content: " ";
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  
  /* Move the pseudo-element back away from the camera,
   * then scale it back up to fill the viewport.
   * Because the pseudo-element is further away, it appears to move more slowly, like in real life. */
  transform: translateZ(-1px) scale(1.5);
  /* Force the background image to fill the whole element. */
  background-size: 100%;
  /* Keep the image from overlapping sibling elements. */ 
  z-index: -1;
}

/* The styling for the static div. */
.page {
  position: relative;
  /* The height of the container. Must be set, but it doesn't really matter what the value is. */
  height: 120vh;
  
  /* For text formatting. */
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  text-shadow: 0 s 1px #000;
  font-family: 'Rock Salt', cursive;
  font-size: 150%;
  background-image: url('green.jpg');
}

/* Sets the actual background images to adorable kitties. This part is crucial. */
.bg1::after {
  font-family: 'Rock Salt', cursive;
  background-image: url('red.jpg');
}

.bg2::after {
  font-family: 'Rock Salt', cursive;
  background-image: url('blue.jpg');
}