/* CSS Custom function in revealjs */
:root{
	--kenburns-duration: 20s;
	--parallax-duration: 60s;
}

/* Images sizes */

figure.big img{
	width: 50%;
}

figure.medium img{
	width: 20%;
	min-width: 320px;
}

figure.small img{
	width: 10%;
	min-width: 210px;
}


/* Ken Burns effect */
.kenburns {
  animation: kenburnseffect var(--kenburns-duration) ease;
  -ms-animation: kenburnseffect var(--kenburns-duration) ease;
  -webkit-animation: kenburnseffect var(--kenburns-duration) ease;
  -0-animation: kenburnseffect var(--kenburns-duration) ease;
  -moz-animation: kenburnseffect var(--kenburns-duration) ease;
}

.kenburns.fast {
  animation-duration: calc(var(--kenburns-duration) * 0.8);
}

.kenburns.faster{
  animation-duration: calc(var(--kenburns-duration) / 2);
}

.kenburns.slow{
  animation-duration: calc(var(--kenburns-duration) * 2);
}

.kenburns.slower{
  animation-duration: calc(var(--kenburns-duration) * 3);
}

@-webkit-keyframes kenburnseffect {
  0% {
    -webkit-transform-origin: bottom left;
    -moz-transform-origin: bottom left;
    -ms-transform-origin: bottom left;
    -o-transform-origin: bottom left;
    transform-origin: bottom left;
    transform: scale(1.0);
    -ms-transform: scale(1.0);
    /* IE 9 */
    
    -webkit-transform: scale(1.0);
    /* Safari and Chrome */
    
    -o-transform: scale(1.0);
    /* Opera */
    
    -moz-transform: scale(1.0);
    /* Firefox */
  }
  100% {
    transform: scale(1.2);
    -ms-transform: scale(1.2);
    /* IE 9 */
    
    -webkit-transform: scale(1.2);
    /* Safari and Chrome */
    
    -o-transform: scale(1.2);
    /* Opera */
    
    -moz-transform: scale(1.2);
    /* Firefox */
  }
}


/* Background Parallax Scrolling  */

.parallax-background {
  position: absolute;
  width: 100vw;
  height: 100%;
  overflow: hidden;
  z-index: -10;
}

.layer {
  position: absolute;
  width: 100vw; 
  height: 120vh;
  background-size: cover;
  background-repeat: repeat-y;
}

.layer1 {
  background-image: url('../assets/images/coins.png');
  animation: scrollBackground var(--parallax-duration) linear infinite;
  background-repeat: repeat-y;
}

.layer2 {
  background-image: url('../assets/images/coins.png');
  opacity: 0.8; 
  animation: scrollBackground var(--parallax-duration) linear infinite reverse;
  background-repeat: repeat-y;
}

.layer1.fast, .layer2.fast {
  animation-duration: calc(var(--parallax-duration) / 1.5);
}

.layer1.faster, .layer2.faster{
  animation-duration: calc(var(--parallax-duration) / 3);
}

.layer1.slow, .layer2.slow{
  animation-duration: calc(var(--parallax-duration) * 3);
}

.layer1.slower, .layer2.slower{
  animation-duration: calc(var(--parallax-duration) * 4);
}


@keyframes scrollBackground {
  from {
    transform: translateY(0);
  }
  to {
    transform: translateY(-50vh);
  }
}


/* specific class for css */
.vertical-center{
	margin-top: calc(var(--viewport-height) / 4);
}