/* ============================================
   Stacking Cards 3D (CSS)
   Professional light UI + Lenis smooth scroll
   ============================================ */

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

html {
  scroll-behavior: initial;
  -webkit-text-size-adjust: 100%;
}

html.lenis,
html.lenis body {
  height: auto;
}

.lenis.lenis-smooth {
  scroll-behavior: auto !important;
}

.lenis.lenis-smooth [data-lenis-prevent] {
  overscroll-behavior: contain;
}

.lenis.lenis-stopped {
  overflow: hidden;
}

html,
body {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body::-webkit-scrollbar,
body *::-webkit-scrollbar {
  display: none;
}

body {
  -ms-overflow-style: none;
}

html {
  scrollbar-width: none;
}

img {
  max-width: 100%;
  display: block;
  border: 0;
  user-select: none;
  -webkit-user-drag: none;
}

/* ---------- Tokens ---------- */

:root {
  --size-unit: 16;
  --size-container-ideal: 1440;
  --size-container-min: 992px;
  --size-container-max: 1920px;
  --size-container: clamp(
    var(--size-container-min),
    100vw,
    var(--size-container-max)
  );
  --size-font: calc(
    var(--size-container) / (var(--size-container-ideal) / var(--size-unit))
  );

  --font-sans: "Inter", system-ui, -apple-system, sans-serif;
  --font-serif: "Instrument Serif", Georgia, "Times New Roman", serif;

  --bg: #f0ede6;
  --card: #ffffff;
  --card-2: #fbfaf7;
  --card-3: #f8f7f4;
  --card-4: #faf8f4;
  --card-5: #f7f6f3;
  --ink: #141210;
  --ink-soft: rgba(20, 18, 16, 0.62);
  --ink-mute: rgba(20, 18, 16, 0.4);
  --line: rgba(20, 18, 16, 0.1);
  --line-strong: rgba(20, 18, 16, 0.16);
}

@media screen and (max-width: 991px) {
  :root {
    --size-container-ideal: 834;
    --size-container-min: 768px;
    --size-container-max: 991px;
  }
}

@media screen and (max-width: 767px) {
  :root {
    --size-container-ideal: 390;
    --size-container-min: 480px;
    --size-container-max: 767px;
  }
}

@media screen and (max-width: 479px) {
  :root {
    --size-container-ideal: 390;
    --size-container-min: 320px;
    --size-container-max: 479px;
  }
}

/* ---------- Base ---------- */

body {
  margin: 0;
  color: var(--ink);
  background-color: var(--bg);
  font-family: var(--font-sans);
  font-size: var(--size-font);
  font-weight: 400;
  line-height: 1.45;
}

/* ---------- Section ---------- */

.demo-section {
  justify-content: center;
  padding: 10svh 1.5em;
  display: flex;
}

/* ---------- Card stack ---------- */

.card-stack {
  --stack-row: 100svh;
  --stack-top: 10svh;
  --stack-card-height: calc(var(--stack-row) - 2 * var(--stack-top));
  view-timeline-name: --card-stack;
  grid-auto-rows: var(--stack-row);
  width: 100%;
  max-width: 58em;
  display: grid;
  position: relative;
}

/* ---------- Cards — square, editorial ---------- */

.card-stack__item {
  transform-origin: 50% 100%;
  color: var(--ink);
  top: var(--stack-top);
  height: var(--stack-card-height);
  background-color: var(--card);
  border-radius: 0;
  padding: 2em 2.25em;
  position: sticky;
  overflow: hidden;
  border: 1px solid var(--line);
  box-shadow:
    0 1px 0 rgba(255, 255, 255, 0.7) inset,
    0 28px 56px -36px rgba(20, 18, 16, 0.22);
}

.card-stack__item.is--2 {
  background-color: var(--card-2);
}

.card-stack__item.is--3 {
  background-color: var(--card-3);
}

.card-stack__item.is--4 {
  background-color: var(--card-4);
}

.card-stack__item.is--5 {
  background-color: var(--card-5);
}

/* ---------- Layout ---------- */

.card-stack__item-inner {
  display: flex;
  flex-direction: column;
  height: 100%;
  gap: 1.5em;
  min-height: 0;
}

/* Header: index — rule — tag ............. count */
.card-stack__header {
  display: flex;
  align-items: center;
  gap: 0.85em;
  flex-shrink: 0;
  min-height: 1.25em;
}

.card-stack__index {
  font-size: 0.72em;
  font-weight: 500;
  letter-spacing: 0.06em;
  font-variant-numeric: tabular-nums;
  color: var(--ink);
}

.card-stack__rule {
  flex: 1;
  height: 1px;
  background: var(--line-strong);
  min-width: 2em;
}

.card-stack__tag {
  font-size: 0.68em;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-mute);
}

.card-stack__count {
  font-size: 0.68em;
  font-weight: 400;
  letter-spacing: 0.08em;
  font-variant-numeric: tabular-nums;
  color: var(--ink-mute);
  margin-left: 0.25em;
}

/* Title + description */
.card-stack__item-top {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
  gap: 1.5em 3em;
  align-items: end;
  flex-shrink: 0;
  padding-bottom: 0.25em;
  border-bottom: 1px solid var(--line);
}

.card-stack__item-h {
  margin: 0;
  max-width: 9em;
  font-family: var(--font-serif);
  font-size: clamp(2.35em, 4.4vw, 3.5em);
  font-weight: 400;
  line-height: 0.96;
  letter-spacing: -0.025em;
  color: var(--ink);
}

.card-stack__item-p {
  margin: 0;
  max-width: 28em;
  font-size: 0.92em;
  font-weight: 400;
  line-height: 1.6;
  letter-spacing: -0.01em;
  color: var(--ink-soft);
  padding-bottom: 0.2em;
}

/* Image panel */
.card-stack__item-bottom {
  position: relative;
  flex: 1;
  min-height: 0;
  width: 100%;
  border-radius: 0;
  overflow: hidden;
  background: #ebe7df;
  border: 1px solid var(--line);
}

.card-stack__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
}

.card-stack__item-bottom::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.06);
  background: linear-gradient(
    180deg,
    rgba(20, 18, 16, 0.02) 0%,
    transparent 30%,
    rgba(20, 18, 16, 0.06) 100%
  );
}

/* ---------- Animation index ---------- */

.card-stack__item:nth-child(1) {
  --stack-i: 1;
}

.card-stack__item:nth-child(2) {
  --stack-i: 2;
}

.card-stack__item:nth-child(3) {
  --stack-i: 3;
}

.card-stack__item:nth-child(4) {
  --stack-i: 4;
}

.card-stack__item:nth-child(5) {
  --stack-i: 5;
}

@supports (width: calc(sibling-index() * 1px)) {
  .card-stack__item {
    --stack-i: sibling-index();
  }
}

/* ---------- 3D stack-away ---------- */

@supports (animation-timeline: view()) {
  .card-stack__item {
    animation: card-stack-away linear forwards;
    animation-timeline: --card-stack;
    animation-range: exit-crossing
      calc(var(--stack-i, 1) * var(--stack-row) - 100svh)
      exit-crossing calc(var(--stack-i, 1) * var(--stack-row) - var(--stack-top));
  }

  .card-stack__item:last-of-type {
    animation: none;
  }
}

@keyframes card-stack-away {
  to {
    transform: perspective(60em) rotateX(25deg) scale(0.85);
    filter: brightness(0.45);
  }
}

@media (prefers-reduced-motion: reduce) {
  .card-stack__item {
    animation: none;
  }
}

/* ---------- Mobile ---------- */

@media screen and (max-width: 767px) {
  .demo-section {
    padding-left: 1em;
    padding-right: 1em;
  }

  .card-stack__item {
    padding: 1.35em 1.25em;
  }

  .card-stack__item-inner {
    gap: 1.15em;
  }

  .card-stack__item-top {
    grid-template-columns: 1fr;
    gap: 0.85em;
    align-items: start;
  }

  .card-stack__item-h {
    font-size: 2.2em;
  }

  .card-stack__item-p {
    max-width: none;
  }

  .card-stack__header {
    gap: 0.6em;
  }

  .card-stack__count {
    display: none;
  }
}