/* 第3段階：通常スクロール内のsticky区間。専用ファイル削除で撤去可能。 */
.window-prototype-scroll {
  --window-travel: 0px;
  --window-sticky-top: 0px;
  display: flow-root;
  margin-top: var(--latest-section-gap);
  height: calc(var(--window-height) + var(--window-travel));
}

.window-prototype-scroll > .latest {
  position: sticky;
  top: var(--window-sticky-top);
  margin-top: 0;
  /* 下の.people__innerと同じ75rem上限・セクション左右padding。 */
  --window-inset: max(clamp(2rem, 6vw, 5rem), calc((100% - 75rem) / 2));
}

.window-prototype-scroll > .latest::before {
  left: var(--window-inset);
  right: var(--window-inset);
}

.window-prototype {
  --window-angle: 0deg;
  --window-opacity: 1;
  position: absolute;
  z-index: 10;
  inset: 0 var(--window-inset);
  pointer-events: none;
}

.window-prototype__stage {
  position: absolute;
  inset: 0;
  perspective: clamp(280px, 85vw, 1200px);
  perspective-origin: 50% 50%;
}

.window-prototype__leaf {
  position: absolute;
  top: 0;
  bottom: 0;
  box-sizing: border-box;
  width: 50%;
  border: 1px solid #000;
  background: #fff;
  backface-visibility: hidden;
  opacity: var(--window-opacity);
  /* transitionは設けず、逆スクロールも同じ位置・角度に直結させる。 */
}

/* 外周はleafのborderだけ。内部は単線の縦1本・横1本（SPは横2本）。 */
.window-prototype__bars {
  position: absolute;
  inset: 0;
  display: grid;
  grid-template-columns: 1fr 1px 1fr;
  grid-template-rows: 1fr 1px 1fr;
}

.window-prototype__bar--vertical {
  grid-column: 2;
  grid-row: 1 / -1;
  background: #000;
}

.window-prototype__bar--horizontal {
  grid-column: 1 / -1;
  grid-row: 2;
  background: #000;
}

.window-prototype__bar--second {
  display: none;
}

.window-prototype__leaf--left {
  left: 0;
  transform-origin: left center;
  transform: rotateY(var(--window-angle));
}

.window-prototype__leaf--right {
  right: 0;
  transform-origin: right center;
  transform: rotateY(calc(-1 * var(--window-angle)));
}

.window-prototype__leaf--top {
  display: none;
}

@media (max-width: 767px) {
  .window-prototype-scroll > .latest {
    --window-inset: 16px;
  }

  .window-prototype__stage {
    perspective: 900px;
    perspective-origin: center top;
  }

  .window-prototype__leaf--left,
  .window-prototype__leaf--right {
    display: none;
  }

  .window-prototype__leaf--top {
    display: block;
    left: 0;
    width: 100%;
    transform-origin: center top;
    transform: rotateX(calc(-1 * var(--window-angle)));
  }

  .window-prototype__leaf--top .window-prototype__bars {
    grid-template-rows: 1fr 1px 1fr 1px 1fr;
  }

  .window-prototype__leaf--top .window-prototype__bar--second {
    display: block;
    grid-row: 4;
  }

}

@media (prefers-reduced-motion: reduce) {
  .window-prototype-scroll {
    height: auto;
  }

  .window-prototype-scroll > .latest {
    position: relative;
    top: auto;
  }

  .window-prototype {
    display: none;
  }
}