:root {
  --timeline-line-color: #7f8c8d;
}

body {
  --background: #efefef;
  --body-font-size: clamp(1.13rem, calc(1.08rem + 0.22vw), 1.25rem);

  background: var(--background);
  font-size: var(--body-font-size);
}

header,
footer {
  background: var(--timeline-line-color);
  display: grid;
  height: 50dvh;
  place-content: center;
  text-align: center;
}

.timeline {
  container: timeline-container / inline-size;

  &-group {
    display: grid;
    gap: 1rem;
    grid-template-areas:
      "point date"
      "point event";
    margin-inline: 1rem;

    @container timeline-container (min-width: 80ch) {
      grid-template-areas: "date point event";
      grid-template-columns: 8fr 1fr 8fr;
      place-content: center;

      &:nth-child(even) {
        grid-template-areas: "event point date";

        .timeline-date {
          --translation: -100px;
          justify-content: flex-start;
        }

        .timeline-event {
          --translation: -100px;
          margin-inline-start: auto;
        }
      }
    }
  }

  &-event {
    --border-radius: 0.5rem;
    --box-shadow: 0px 12.5px 10px rgba(0, 0, 0, 0.035),
      0px 100px 80px rgba(0, 0, 0, 0.07);
    --easing: cubic-bezier(0.34, 1.56, 0.64, 1);
    --range-start: contain 30%;
    --range-end: contain 50%;
    --translation: 100px;

    grid-area: event;
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);

    > :not(figure) {
      padding-inline: 1rem;
    }

    @container timeline-container (min-width: 80ch) {
      margin-block: 2rem;
      width: min(100% - 1rem, 30cqw);
      position: relative;
    }

    @media (prefers-reduced-motion: no-preference) {
      @supports (animation-timeline: view(block)) {
        opacity: 0;
        animation: slide-in var(--easing) both;
        animation-timeline: view(block);
        animation-range: var(--range-start) var(--range-end);
        transform-origin: center center;
        transform: translateX(var(--translation));
      }
    }

    figure {
      margin: 0;
      width: 100%;
      aspect-ratio: 16/9;
      overflow: hidden;
      border-top-right-radius: var(--border-radius);
      border-top-left-radius: var(--border-radius);
      img {
        display: block;
        height: 100%;
        width: 100%;
        object-fit: cover;
        object-position: center;
      }
    }
  }

  &-point {
    display: grid;
    grid-area: point;
    place-content: center;
    position: relative;
    width: 100%;

    span {
      --point-size: 50px;
      --point-color: #34495e;
      --easing: cubic-bezier(0.34, 1.56, 0.64, 1);
      --range-start: contain 30%;
      --range-end: contain 50%;
      --translation: 100px;

      align-items: center;
      aspect-ratio: 1;
      height: var(--point-size);
      background: var(--point-color);
      border-radius: 100%;
      display: flex;
      flex-direction: column;

      @media (prefers-reduced-motion: no-preference) {
        @supports (animation-timeline: view(block)) {
          animation: scale-up var(--easing) both;
          animation-timeline: view(block);
          animation-range: var(--range-start) var(--range-end);
          transform-origin: center center;
        }
      }
    }

    &::after {
      background: var(--timeline-line-color);
      content: "";
      display: block;
      height: 100%;
      position: absolute;
      left: calc(50% - (10px / 2));
      margin-inline: auto;
      width: 10px;
      top: 0;
      z-index: -1;
    }
  }

  &-date {
    --range-start: contain 30%;
    --range-end: contain 50%;
    --translation: -100px;

    grid-area: date;

    @container timeline-container (min-width: 80ch) {
      --translation: -100px;

      align-items: center;
      display: flex;
      justify-content: flex-end;
    }

    @media (prefers-reduced-motion: no-preference) {
      @supports (animation-timeline: view(block)) {
        animation: fade-in linear both;
        animation-timeline: view(block);
        animation-range: var(--range-start) var(--range-end);
        opacity: 0;
        transform: translateY(var(--translation));
      }
    }
  }
}

@keyframes slide-in {
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

@keyframes scale-up {
  0% {
    scale: 1;
  }
  75% {
    scale: 1.2;
  }
  100% {
    scale: 1;
  }
}

@keyframes fade-in {
  75% {
    opacity: 0;
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

.message {
  background: yellow;
  font-size: 1.5rem;
  padding-inline: 2rem;
  padding-block: 3rem;
  > * {
    width: 60ch;
  }
  @supports (animation-timeline: view()) {
    display: none;
  }
}