@keyframes slidy {
0% { left: 0%; }
20% { left: 0%; }
25% { left: -100%; }
45% { left: -100%; }
50% { left: -200%; }
70% { left: -200%; }
75% { left: -300%; }
95% { left: -300%; }
100% { left: -400%; }
}

figure {margin: 0;}

div#captioned-gallery {width: 100%; overflow: hidden;}

figure.slider { 
  position: relative; width: 500%;
  font-size: 0; animation: 20s slidy infinite; 
}

figure.slider figure { 
  width: 20%; height: auto;
  display: inline-block;  position: inherit;
  }
  
figure.slider img { width: 100%; height: auto; }

figure.slider figure figcaption {position: absolute; bottom: 0;width: 100%;font-size: 2rem; padding: 2rem;}