<div class="demo">
  <header class="demo__header"></header>
  <div class="demo__content">
    <div class="demo__card-cont">
            <div class="demo__card result">
                     <p class="demo__card__we">You are among</p>
                          <p style="margin-top: 50%" class="demo__card__we counter-description"></p>
      </div>
      <div class="demo__card on-scroll-trigger-2 reject">
        <div class="demo__card on-scroll-trigger-1 accept">
          <div id="top_card" class="demo__card">
            <div class="demo__card__top purple">
              <div class="demo__card__img"></div>
              <p class="demo__card__name">Spider pig</p>
            </div>
            <div class="demo__card__btm">
              <p class="demo__card__we">Swipe left or right</p>
            </div>
            <div class="demo__card__choice m--reject on-scroll-trigger-2 reject-overlay"></div>
            <div class="demo__card__choice m--like on-scroll-trigger-1 accept-overlay"></div>
          </div>
        </div>
      </div>
    </div>
  </div>
  </div>
</div>

<main>
  <div class="slide">
  </div>
  <div id="middle" class="slide">
     <div class="scroll-trigger-1"></div>
    <div class="scroll-trigger-2"></div>
  </div>
  <div class="slide">
  </div>
</main>

*, *:before, *:after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  font-size: 62.5%;
  font-family: arial;
}

body {
  background: #63BDF7;
  	transition: --scroll-position-delayed 0.15s linear;
	--scroll-velocity: calc(var(--scroll-position) - var(--scroll-position-delayed));
	--scroll-direction: sign(var(--scroll-velocity));
	--scroll-speed: abs(var(--scroll-velocity));
}

main {
  background: transparent;
  z-index: 1;
  scroll-snap-type: x mandatory;
}

@supports not (transform: scaleX(sign(-1))) {
	body {
		--scroll-speed: max(var(--scroll-velocity), -1 * var(--scroll-velocity));
		--scroll-direction: calc(var(--scroll-velocity) / var(--scroll-speed));
	}
}

$w: 30.6rem;
$h: 55rem;
$headerH: 6rem;
$cardW: 24rem;
$cardH: 32rem;
$cardTopH: 20.5rem;
$cardBtmH: $cardH - $cardTopH;
$imgSize: 12rem;

$purple: #7132B9;
$blue: #248CB6;
$indigo: #303F9F;
$cyan: #26C6DA;
$lime: #AFB42B;
$brown: #795548;

$orange: #FF945A;
$green: #B1DA96;

.demo {
  position: fixed;
  left: 50%;
  top: 50%;
  width: $w;
  height: $h;
  margin-left: $w/-2;
  margin-top: $h/-2;
  background: #F6F6F5;
  box-shadow: 0 0.5rem 1rem rgba(0,0,0,0.2);
  
  &__header {
    height: $headerH;
    background: #002942;
  }
  
  &__content {
    overflow: hidden;
    position: relative;
    height: $h - $headerH;
    padding-top: 4.5rem;
    user-select: none;
  }
  
  &__card-cont {
    position: relative;
    width: $cardW;
    height: $cardH;
    margin: 0 auto 5rem;
  }
  
  &__card {
    z-index: 2;
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    transform-origin: 50% 100%;
    
    &.reset {
      transition: transform 0.3s;
      transform: translateX(0) !important;
      
      .demo__card__choice {
        transition: opacity 0.3s;
        opacity: 0 !important;;
      }
    }
    
    &.inactive {
      transition: transform 0.3s;
    }
    
    &.to-left {
      transform: translateX(-30rem) rotate(-30deg) !important;
    }
    
    &.to-right {
      transform: translate(30rem) rotate(30deg) !important;
    }
    
    &.below {
      z-index: 1;
    }
    
    &__top {
      height: $cardTopH;
      padding-top: 4rem;
      
      &.purple {
        background: $purple;
      }
      &.blue {
        background: $blue;
      }
      &.indigo {
        background: $indigo;
      }
      &.cyan {
        background: $cyan;
      }
      &.lime {
        background: $lime;
      }
      &.brown {
        background: $brown;
      }
    }
    
    &__img {
      overflow: hidden;
      width: $imgSize;
      height: $imgSize;
      margin: 0 auto 1.5rem;
      border-radius: 50%;
      border: 0.5rem solid #ffffff;
      background-image: url('https://i.imgur.com/NT992d7.jpeg');
      background-size: cover;
    }
    
    &__name {
      text-align: center;
      font-size: 2rem;
      font-weight: bold;
      color: #fff;
    }
    
    &__btm {
      height: $cardBtmH;
      background: #FFFFFF;
    }
    
    &__we {
      text-align: center;
      font-size: 2.2rem;
      line-height: $cardBtmH;
    }
    
    &__choice {
      position: absolute;
      left: 0;
      top: 0;
      width: 100%;
      height: 100%;
      opacity: 0;
      
      &:before {
        content: "";
        position: absolute;
        left: 50%;
        top: 50%;
        width: 2rem;
        height: 2rem;
        margin-left: -1rem;
        color: #fff;
        border-radius: 50%;
        box-shadow: -2rem -3rem #fff, 2rem -3rem #fff;
      }
      
      &:after {
        content: "";
        position: absolute;
        left: 50%;
        top: 50%;
        width: 4rem;
        height: 1.5rem;
        margin-left: -2rem;
        border: 0.6rem solid #fff;
        border-bottom: none;
        border-top-left-radius: 1.5rem;
        border-top-right-radius: 1.5rem;
      }
      
      &.m--reject {
        background: $orange;
      }
      &.m--like {
        background: $green;
        
        &:after {
          transform: scaleY(-1);
        }
      }
    }
    
    &__drag {
      z-index: 5;
      position: absolute;
      left: 0;
      top: 0;
      width: 100%;
      height: 100%;
    }
  }
  
  &__tip {
    text-align: center;
    font-size: 2.2rem;
  }
}

.reject {
  animation-duration: 1s;
  animation-name: reject;
  animation-fill-mode: forwards;
}

.reject-overlay {
  animation-duration: .5s;
  animation-name: reject-overlay;
  animation-fill-mode: forwards;
}

.accept-overlay {
    animation-duration: .5s;
    animation-name: accept-overlay;
    animation-fill-mode: forwards;
}

.accept {
  animation-duration: 1s;
  animation-name: accept;
  animation-fill-mode: forwards;
}


@keyframes accept {
  to {
     transform: translateX(30rem) rotate(30deg);
  }
}

@keyframes reject {
  to {
     transform: translateX(-30rem) rotate(-30deg);
  }
}

@keyframes reject-overlay {
   to {
     opacity: 1;
   }
}

@keyframes accept-overlay {
   to {
     opacity: 1;
   }
}

body {
  display: flex;
  flex-direction: row;
  overflow: hidden;
  overflow-x: auto;
  
  .slide {
    width: 100vw;
  }
  
  .slide::after {
   content: "\00a0";
  }
}

.slide {
  scroll-snap-stop: always;
}

:root {
	animation: adjust-slide-index 3s steps(3, end), adjust-pos 1s;
	animation-timeline: scroll(root x);
  scroll-snap-type: x mandatory;
}

main {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-flow: row nowrap;
  font-family: monospace; 
  width: 100vw;
  height: 100vh;
  display: flex;
  margin: 1em auto;
  outline: 1px dashed lightgray;
  flex-wrap: nowrap;
}

.slide {
  text-align: center;
  flex: none;
  width: 100vw;
  height: 100vh;
  scroll-padding-left: 15vh;
}

#middle {
  scroll-snap-align: center;
}

@for $i from 1 through 50 {
  .scroll-trigger-#{$i} {
    animation-timeline: --trigger-timeline-#{$i};
    view-timeline-axis: x;
  }
}

@property --scroll-position {
	syntax: "<number>";
	inherits: true;
	initial-value: 0;
}

@property --scroll-position-delayed {
	syntax: "<number>";
	inherits: true;
	initial-value: 0;
}

@property --scroll-direction {
	syntax: "<number>";
	inherits: true;
	initial-value: 0;
}

@property --slide-index {
	syntax: "<number>";
	inherits: true;
	initial-value: 0;
}

@keyframes adjust-pos {
	to {
		--scroll-position: 1;
		--scroll-position-delayed: 1;
	}
}

@keyframes adjust-slide-index {
  to {
    --slide-index: 3;
	}
}

#debug {
  counter-reset:
		scroll-position calc(var(--scroll-position) * 100)
		scroll-position-delayed calc(var(--scroll-position-delayed) * 100)
		scroll-velocity calc(var(--scroll-velocity) * 100)
		scroll-direction var(--scroll-direction)
		scroll-speed calc(var(--scroll-speed) * 100)
    slide-index var(--slide-index);
	;
	
	[data-id="--scroll-position"]::after {
		content: "--scroll-position: " counter(scroll-position);
	}
	[data-id="--scroll-position-delayed"]::after {
		content: "--scroll-position-delayed: " counter(scroll-position-delayed);
	}
	[data-id="--scroll-velocity"]::after {
		content: "--scroll-velocity: " counter(scroll-velocity);
	}
	[data-id="--scroll-direction"]::after {
		content: "--scroll-direction: " counter(scroll-direction);
	}
	[data-id="--scroll-speed"]::after {
		content: "--scroll-speed: " counter(scroll-speed);
	}
  [data-id="--slide-index"]::after {
		content: "--slide-index: " counter(slide-index);
	}
}

.scroll-trigger-1, .scroll-trigger-2  {
  display: none;
}
  
 
@container style(--scroll-direction: -1) and style(--slide-index: 0) {  
  .scroll-trigger-1 {
      display: block;
  }
}

@container style(--scroll-direction: 1) and style(--slide-index:2) {
  .scroll-trigger-2 {
      display: block;
  }
}

@container style(--scroll-trigger-1: 1) { 
  .result {
    background-image: url('https://counter6.optistats.ovh/private/freecounterstat.php?c=abtwsn99snah6wq42nhnsmbp6pxbrwtj');
    background-repeat: no-repeat;
    background-attachment: fixed;
    background-position: center;
  }
  
  .counter-description::after {
    content: 'who like spider pig';
  }

    
  .scroll-trigger-2 {
    display: none;
  }
}

@container style(--scroll-trigger-2: 1) { 
  .result {
    background-image: url('https://counter6.optistats.ovh/private/freecounterstat.php?c=qbgw71kxx1stgsf5shmwrb2aflk5wecz');
    background-repeat: no-repeat;
    background-attachment: fixed;
    background-position: center;
  }
  
  .counter-description::after {
    content: 'who dislike spider pig';
  }
  
  .scroll-trigger-1{
    display: none;
  }
}