:root {
  --card-height: 40vw;
  --card-margin: 4vw;
  --card-top-offset: 1em;
  --outline-width: 0px;
}

#cards {
  padding-bottom: calc(var(--numcards) * var(--card-top-offset)); /* Make place at bottom, as items will slide to that position*/
  margin-bottom: var(--card-margin); /* Don't include the --card-margin in padding, as that will affect the scroll-timeline*/
}

#card_1 {
  --index: 1;
}

#card_2 {
  --index: 2;
}

#card_3 {
  --index: 3;
}


.card {
  position: sticky;
  top: 0;
  padding-top: calc(var(--index) * var(--card-top-offset));
}

@supports (animation-timeline: works) {

  @scroll-timeline cards-element-scrolls-in-body {
    source: selector(body);
    scroll-offsets:
      /* Start when the start edge touches the top of the scrollport */
      selector(#cards) start 1,
      /* End when the start edge touches the start of the scrollport */
      selector(#cards) start 0
    ;
    start: selector(#cards) start 1; /* Start when the start edge touches the top of the scrollport */
    end: selector(#cards) start 0; /* End when the start edge touches the start of the scrollport */
    time-range: 4s;
  }

  .card {
    --index0: calc(var(--index) - 1); /* 0-based index */
    --reverse-index: calc(var(--numcards) - var(--index0)); /* reverse index */
    --reverse-index0: calc(var(--reverse-index) - 1); /* 0-based reverse index */
  }
  
  .card__content {
    transform-origin: 50% 0%;
    will-change: transform;

    --duration: calc(var(--reverse-index0) * 1s);
    --delay: calc(var(--index0) * 1s);

    animation: var(--duration) linear scale var(--delay) forwards;
    animation-timeline: cards-element-scrolls-in-body;
  }

  @keyframes scale {
    to {
      transform:
        scale(calc(
          1.1
          -
          calc(0.1 * var(--reverse-index))
        ));
    }
  }
}

/** PAGE STYLING **/

* { /* Poor Man's Reset */
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background: rgb(58 29 43);
  /*background-image: url("pics/jam1.jpg");*/
  background-repeat:no-repeat;
  background-size:cover;
  color: rgb(255, 255, 255);
  text-align: center;

  font-size: calc(1em + 0.5vw);
}

header,
main {
  width: 80vw;
  margin: 0 auto;
}

header {
  height: 100vh;
  display: grid;
  place-items: center;
}

#cards {
  list-style: none;
  outline: calc(var(--outline-width) * 10) solid blue;
  
  display: grid;
  grid-template-columns: 1fr;
  grid-template-rows: repeat(var(--numcards), var(--card-height));
  gap: var(--card-margin);
}

.card {
  outline: var(--outline-width) solid hotpink;
}

.card__content {
  box-shadow: 0 0.2em 1em rgba(0, 0, 0, 0.1), 0 1em 2em rgba(0, 0, 0, 0.1);
  background: rgb(255, 255, 255);
  color: rgb(10, 5, 7);
  border-radius: 1em;
  overflow: hidden;

  display: grid;
  grid-template-areas: "text img";
  grid-template-columns: 1fr 1fr;
  grid-template-rows: auto;

  align-items: stretch;
  outline: var(--outline-width) solid lime;
}

.card__content > div {
  grid-area: text;
  width: 80%;
  place-self: center;
  text-align: left;

  display: grid;
  gap: 1em;
  place-items: start;
}

.card__content > figure {
  grid-area: img;
  overflow: hidden;
}

.card__content > figure > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

h1 {
  font-weight: 300;
  font-size: 3.5em;
}

h2 {
  font-weight: 300;
  font-size: 2.5em;
}

p {
  font-family: sans-serif;
  font-weight: 300;
  line-height: 1.42;
}

.button-reload {
  padding: 15px 25px;
  font-size: 24px;
  text-align: center;
  cursor: pointer;
  outline: none;
  color: #fff;
  background-color: #04AA6D;
  border: none;
  border-radius: 15px;
  box-shadow: 0 9px #999;
}

.button:hover {background-color: #3e8e41}

.button:active {
  background-color: #3e8e41;
  box-shadow: 0 5px #666;
  transform: translateY(4px);
}