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

html,
body {
  height: 100%;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background-color: #ebe5dd;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow: hidden;
}

img {
  display: block;
  max-width: 100%;
  user-select: none;
  -webkit-user-drag: none;
}

/* --------------------------------------------------------------------------
   Stage
   -------------------------------------------------------------------------- */

.demo-section {
  background-color: #ebe5dd;
  justify-content: center;
  align-items: center;
  min-height: 100svh;
  font-size: 1vw;
  display: flex;
  overflow: clip;
}

/* --------------------------------------------------------------------------
   Collage shell — fixed em-based layout (scales with font-size / viewport)
   -------------------------------------------------------------------------- */

.interactive-collage {
  width: 63.75em;
  height: 37em;
  flex: none;
  cursor: default;
}

.interactive-collage__collection {
  width: 100%;
  height: 100%;
}

.interactive-collage__list {
  width: 100%;
  height: 100%;
  position: relative;
}

.interactive-collage__item {
  z-index: 0;
  position: absolute;
  top: 0;
  left: 0;
  cursor: pointer;
  /* Isolate paint so GPU can composite each card independently */
  contain: layout style;
  isolation: isolate;
}

.interactive-collage__item.is--1 {
  top: 6em;
}

.interactive-collage__item.is--2 {
  top: 17em;
  left: 5em;
}

.interactive-collage__item.is--3 {
  z-index: 1;
  top: 14em;
  left: 13.5em;
}

.interactive-collage__item.is--4 {
  left: 24em;
}

.interactive-collage__item.is--5 {
  z-index: 3;
  top: auto;
  bottom: 0;
  left: 26em;
}

.interactive-collage__item.is--6 {
  z-index: 2;
  top: 9em;
  left: 31.5em;
}

.interactive-collage__item.is--7 {
  z-index: 1;
  top: 16em;
  left: 39em;
}

.interactive-collage__item.is--8 {
  top: 5em;
  left: auto;
  right: 0;
}

/* Focused card rises above siblings (instant z so it never paints under) */
.interactive-collage__item[data-interactive-collage-focus] {
  z-index: 10;
}

/* --------------------------------------------------------------------------
   Inner wrapper — GSAP animates xPercent / yPercent / scale here
   -------------------------------------------------------------------------- */

.interactive-collage__item-inner {
  transform-origin: center center;
  will-change: transform;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  /* Promote to its own layer once, avoid thrashing */
  transform: translateZ(0);
}

/* --------------------------------------------------------------------------
   Cards
   -------------------------------------------------------------------------- */

.demo-card {
  aspect-ratio: 1;
  width: 16.25em;
  position: relative;
  overflow: hidden;
  background-color: #d4cdc3;
  box-shadow:
    0 0.15em 0.6em rgba(40, 30, 20, 0.08),
    0 0.4em 1.2em rgba(40, 30, 20, 0.06);
  /* Soft shadow lift while focused — CSS only, no layout cost */
  transition: box-shadow 1s cubic-bezier(0.16, 1, 0.3, 1);
}

.interactive-collage__item[data-interactive-collage-focus] .demo-card {
  box-shadow:
    0 0.35em 1em rgba(40, 30, 20, 0.12),
    0 0.9em 2.4em rgba(40, 30, 20, 0.14);
}

.demo-card.is--landscape {
  aspect-ratio: 4 / 3;
  width: 20em;
}

.demo-card.is--portrait {
  aspect-ratio: 3 / 4;
  width: 15em;
}

.cover-image {
  object-fit: cover;
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  pointer-events: none;
  will-change: transform;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  transform: translateZ(0);
}

/* --------------------------------------------------------------------------
   Responsive — larger em base on tablet / mobile
   -------------------------------------------------------------------------- */

@media screen and (max-width: 991px) {
  .demo-section {
    font-size: 2.125vw;
  }
}

@media screen and (max-width: 600px) {
  .demo-section {
    font-size: 2.6vw;
    padding: 1.5rem;
  }

  body {
    overflow: auto;
  }
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  .interactive-collage__item-inner {
    transition: none !important;
  }
}