<div class="untitled">
  <div class="untitled__slides">
    <div class="untitled__slide">
      <div class="untitled__slideBg"></div>
      <div class="untitled__slideContent">
        <span>London</span> 
        <span>Scout</span>
        <a class="button" href="https://unsplash.com/@scoutthecity" target="/black">Unsplash Profile</a>
      </div>
    </div>
    <div class="untitled__slide">
      <div class="untitled__slideBg"></div>
      <div class="untitled__slideContent">
        
        <span>Vladimir</span> 
        <span>Kudinov</span>
        <a class="button" href="https://unsplash.com/@madbyte" target="/black">Unsplash Profile</a>
      </div>
    </div>
    <div class="untitled__slide">
      <div class="untitled__slideBg"></div>
      <div class="untitled__slideContent">
        <span>Macio</span> 
        <span>Amorim</span>
        <a class="button" href="https://unsplash.com/@maicoamorim" target="/black">Unsplash Profile</a>
      </div>
    </div>
    <div class="untitled__slide">
      <div class="untitled__slideBg"></div>
      <div class="untitled__slideContent">
        <span>Mario</span> 
        <span>Calvo</span>
        <a class="button" href="https://unsplash.com/@mariocalvo" target="/black">Unsplash Profile</a>
      </div>
    </div>
  </div>
  <div class="untitled__shutters"></div>
</div>

$t: 2.5s;
$e1: cubic-bezier(0.8, 0.00, 0.1, 1);
$e2: cubic-bezier(0.600, 0.040, 0.980, 0.335);
$er: linear;

$color: hsl(15,75%,40%);
$font: 'Abril Fatface', sans-serif;

$slides: 4;
$images: url(https://unsplash.it/g/1500/2200?image=838) url(https://unsplash.it/g/1500/1000?image=1078) url(https://unsplash.it/g/1500/1000?image=1077)  url(https://unsplash.it/g/1500/1200?image=345);

html, body{
  width: 100vw;
  height: 100vh;
  overflow: hidden;
}

.untitled{  
  position: absolute;
  height: 100%;
  width: 100%;
  @keyframes rotateHue {
    0%{ filter: hue-rotate(0deg); }
    20%{ filter: hue-rotate(0deg); }
    25%{ filter: hue-rotate(90deg); }
    45%{ filter: hue-rotate(90deg); }
    50%{ filter: hue-rotate(180deg); }
    70%{ filter: hue-rotate(180deg); }
    75%{ filter: hue-rotate(270deg); }
    95%{ filter: hue-rotate(270deg); }
    100%{ filter: hue-rotate(360deg); }
  }
  animation: rotateHue infinite $t*$slides*2 linear;
  animation-delay: $t/4;
  
  &__shutters{
    position: absolute;
    height: 150vmax;
    width: 150vmax;
    left: calc(50% - 75vmax);
    top: calc(50% - 75vmax);
    pointer-events: none;
    z-index: 2;
    @keyframes rotateFrame{
      0%{ transform: rotate(0deg);}
      100%{ transform: rotate(180deg);}
    }
    animation: rotateFrame $t*4 $er infinite;

    &:before, &:after{
      content: '';
      position: absolute;
      height: 100%;
      width: 100%;
      left: 50%;
      transform: translate3d(-50%, 0, 0);
      background-color: $color;
      pointer-events: auto;
    }
    &:before{
      bottom: 50%;
      @keyframes openTop{
        0%{ transform: translate3d(-50%, 0, 0); animation-timing-function: $e1; }
        40%{ transform: translate3d(-50%, -65vmax, 0); animation-timing-functon: $e2; }
        70%{ transform: translate3d(-50%, -65vmax, 0); animation-timing-functon: $e2; }
        100%{ transform: translate3d(-50%, 0, 0); animation-timing-function: $e2; }
      }
      animation: openTop $t*2 infinite;
    }
    &:after{
      top: 50%;
      @keyframes openBottom{
        0%{ transform: translate3d(-50%, 0, 0); animation-timing-function: $e1; }
        40%{ transform: translate3d(-50%, 65vmax, 0); animation-timing-functon: $e2; }
        70%{ transform: translate3d(-50%, 65vmax, 0); animation-timing-functon: $e2; }
        100%{ transform: translate3d(-50%, 0, 0); animation-timing-function: $e2; }
      }
      animation: openBottom $t*2 infinite;
    }
  }
  
  &__slides{
    position: absolute;
    height: 100%;
    width: 100%;
    top: 0;
    left: 0;
    background-color: $color;
  }
  &__slide{
    position: absolute;
    height: 100%;
    width: 100%;
    opacity: 0;
    @keyframes showHideSlide{
      0%{
        opacity: 1; 
        pointer-events: auto;
        z-index: 1;
      }
      #{100% / $slides}{
        opacity: 0;
        pointer-events: none;
        z-index: -1;
      }
      100%{
        opacity: 0;
        pointer-events: none;
        z-index: -1;
      }
    }
    animation: showHideSlide infinite $t*$slides*2 steps(1);
    @for $i from 1 through $slides{
      &:nth-child(#{$i}){ 
        animation-delay: $t * ($i - 1) * 2;
        .untitled__slideBg{
          background-image: nth($images, $i);
        }
      } 
    }
  }
  &__slideBg{
    position: relative;
    height: 100%;
    width: 100%;
    top: 0;
    left: 0;
    background-size: cover;
    background-position: center;
    background-color: $color;
    background-blend-mode: hard-light;
    opacity: 1;
    z-index: -1;
    @keyframes bgInOut{
      0%{ transform: rotate(-45deg) scale(1.1); animation-timing-function: cubic-bezier(0.165, 0.840, 0.440, 1.000);}
      33%{ transform: rotate(0deg);}
      50%{ transform: rotate(0deg); }
      66%{ transform: rotate(0deg); animation-timing-function: cubic-bezier(0.895, 0.030, 0.685, 0.220); }
      100%{ transform: rotate(45deg) scale(0.9);}
    }
    animation: bgInOut $t*4 -$t*2 infinite; 
  }
  &__slideContent{
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate3d(-50%,-50%,0);
    color: white;
    font-family: $font;
    line-height: 0.8;
    letter-spacing: -0.025em;
    z-index: 2;
    opacity: 1;
    text-shadow: 0 0 0.5em rgba($color,0.25);
    mix-blend-mode: lighten;
    span{
      display: block;
      font-size: 15vmin;
    }
  }
}
.button{
  font-family:'Roboto Mono', sans-serif;
  text-decoration: none;
  font-weight: 800;
  text-transform: uppercase;
  font-size: 2vmin;
  display: inline-block;
  position: relative;
  border: 3px solid white;
  box-shadow: -0.5vmin 0.5vmin 0 rgba(white, 0.5);
  background: transparent;
  margin-top: 5vmin;
  mix-blend-mode: lighten;
  color: white;
  padding: 2vmin 2vmin 1.8vmin 2vmin;
  letter-spacing: 0.1em;
  text-shadow: none;
  line-height: 1;
  transform: translate3d(0.5vmin, -0.5vmin, 0);
  transition: all 100ms linear;
  &:hover{ 
    transform: translate3d(1vmin, -1vmin, 0);
    box-shadow: -1vmin 1vmin 0 rgba(white, 0.5);
    background: white;
    color: black;
  }
  &:active{ 
    transform: translate3d(0px, 0px, 0);
    box-shadow: -0px 0px 0 rgba(white, 0.5);
  }
}

//Spark of inspiration came from this movie trailer:
// https://www.youtube.com/watch?v=qSpBnZa3Bek