Pure CSS Background Slideshow With Ken Burns Effect

A fancy responsive background slideshow which uses CSS3 to fade through a group of background images with a Ken Burns effect.

How to use it:

Create a group of DIV elements with background images as follows:

<div class="slideshow">
  <div class="slideshow-image" style="background-image: url('1.jpg')"></div>
  <div class="slideshow-image" style="background-image: url('2.jpg')"></div>
  <div class="slideshow-image" style="background-image: url('3.jpg')"></div>
  <div class="slideshow-image" style="background-image: url('4.jpg')"></div>
</div>

The core CSS/CSS3 styles for the background slideshow.

.slideshow {
  position: absolute;
  width: 100vw;
  height: 100vh;
  overflow: hidden;
}
.slideshow-image {
  position: absolute;
  width: 100%;
  height: 100%;
  background: no-repeat 50% 50%;
  background-size: cover;
  -webkit-animation-name: kenburns;
  animation-name: kenburns;
  -webkit-animation-timing-function: linear;
  animation-timing-function: linear;
  -webkit-animation-iteration-count: infinite;
  animation-iteration-count: infinite;
  -webkit-animation-duration: 16s;
  animation-duration: 16s;
  opacity: 1;
  -webkit-transform: scale(1.2);
  transform: scale(1.2);
}
.slideshow-image:nth-child(1) {
  -webkit-animation-name: kenburns-1;
  animation-name: kenburns-1;
  z-index: 3;
}
.slideshow-image:nth-child(2) {
  -webkit-animation-name: kenburns-2;
  animation-name: kenburns-2;
  z-index: 2;
}
.slideshow-image:nth-child(3) {
  -webkit-animation-name: kenburns-3;
  animation-name: kenburns-3;
  z-index: 1;
}
.slideshow-image:nth-child(4) {
  -webkit-animation-name: kenburns-4;
  animation-name: kenburns-4;
  z-index: 0;
}

Create the Ken Burns effect in the CSS keyframes.

@-webkit-keyframes 
kenburns-1 {  0% {
 opacity: 1;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
 1.5625% {
 opacity: 1;
}
 23.4375% {
 opacity: 1;
}
 26.5625% {
 opacity: 0;
 -webkit-transform: scale(1);
 transform: scale(1);
}
 100% {
 opacity: 0;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
 98.4375% {
 opacity: 0;
 -webkit-transform: scale(1.21176);
 transform: scale(1.21176);
}
 100% {
 opacity: 1;
}
}
@keyframes 
kenburns-1 {  0% {
 opacity: 1;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
 1.5625% {
 opacity: 1;
}
 23.4375% {
 opacity: 1;
}
 26.5625% {
 opacity: 0;
 -webkit-transform: scale(1);
 transform: scale(1);
}
 100% {
 opacity: 0;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
 98.4375% {
 opacity: 0;
 -webkit-transform: scale(1.21176);
 transform: scale(1.21176);
}
 100% {
 opacity: 1;
}
}
@-webkit-keyframes 
kenburns-2 {  23.4375% {
 opacity: 1;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
 26.5625% {
 opacity: 1;
}
 48.4375% {
 opacity: 1;
}
 51.5625% {
 opacity: 0;
 -webkit-transform: scale(1);
 transform: scale(1);
}
 100% {
 opacity: 0;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
}
@keyframes 
kenburns-2 {  23.4375% {
 opacity: 1;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
 26.5625% {
 opacity: 1;
}
 48.4375% {
 opacity: 1;
}
 51.5625% {
 opacity: 0;
 -webkit-transform: scale(1);
 transform: scale(1);
}
 100% {
 opacity: 0;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
}
@-webkit-keyframes 
kenburns-3 {  48.4375% {
 opacity: 1;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
 51.5625% {
 opacity: 1;
}
 73.4375% {
 opacity: 1;
}
 76.5625% {
 opacity: 0;
 -webkit-transform: scale(1);
 transform: scale(1);
}
 100% {
 opacity: 0;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
}
@keyframes 
kenburns-3 {  48.4375% {
 opacity: 1;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
 51.5625% {
 opacity: 1;
}
 73.4375% {
 opacity: 1;
}
 76.5625% {
 opacity: 0;
 -webkit-transform: scale(1);
 transform: scale(1);
}
 100% {
 opacity: 0;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
}
@-webkit-keyframes 
kenburns-4 {  73.4375% {
 opacity: 1;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
 76.5625% {
 opacity: 1;
}
 98.4375% {
 opacity: 1;
}
 100% {
 opacity: 0;
 -webkit-transform: scale(1);
 transform: scale(1);
}
}
@keyframes 
kenburns-4 {  73.4375% {
 opacity: 1;
 -webkit-transform: scale(1.2);
 transform: scale(1.2);
}
 76.5625% {
 opacity: 1;
}
 98.4375% {
 opacity: 1;
}
 100% {
 opacity: 0;
 -webkit-transform: scale(1);
 transform: scale(1);
}
}