Restore sticky card stack: stepped top + z-index, fix scroll runway.

Reverts broken is-stuck body hiding and same-top layout from recent fixes.
Each layer sticks lower (L0–L6); higher z covers previous card on scroll.
Scroll pull was ~2.75rem (page only 1060px) — now 70vh per layer (~4k scroll).

Co-authored-by: Cursor <cursoragent@cursor.com>

shared/stack-layout.css

@@ -1,4 +1,3 @@
-/* Overlapping scroll slots — each layer covers the one below via z-index */
 .scroll-section {
   height: var(--stack-slot);
   position: relative;
@@ -10,7 +9,7 @@
 
 .scroll-section--final {
   height: var(--stack-slot-last);
-  min-height: 260px;
+  min-height: 280px;
 }
 
 .stack-stop,
@@ -18,18 +17,3 @@
   height: 2rem;
   margin-bottom: 3rem;
 }
-
-/* Body visible only when card is stuck on the stack — next card covers previous */
-.scroll-section:not(.is-stuck) .body,
-.scroll-section:not(.is-stuck) .layer-inner,
-.scroll-section:not(.is-stuck) .frame-body,
-.scroll-section:not(.is-stuck) .unit-body {
-  visibility: hidden;
-  min-height: 0;
-  height: 0;
-  padding-top: 0;
-  padding-bottom: 0;
-  border: none;
-  box-shadow: none;
-  overflow: hidden;
-}

shared/stack-scroll.js

@@ -1,32 +1,23 @@
-/** Scroll depth + jump + hide upcoming cards until they cover the stack */
+/** Scroll depth + jump-to-layer for stack variants */
 export function initStackScroll(options = {}) {
   const {
     sectionSelector = '.scroll-section',
     depthEl = document.getElementById('depth'),
     depthPrefix = 'L',
     tabSelector = '[data-goto], .jump',
-    panelSelector = '.folder, .layer, .frame, .unit',
   } = options;
 
   const sections = document.querySelectorAll(sectionSelector);
   if (!sections.length) return;
 
-  const reveal = () => {
-    const v = getComputedStyle(document.documentElement).getPropertyValue('--stack-reveal').trim();
-    return parseFloat(v) || 344;
-  };
-
   const mid = () => window.innerHeight * 0.42;
 
   function updateDepth() {
-    const rLine = reveal();
     let active = 0;
-
     sections.forEach((sec) => {
       const r = sec.getBoundingClientRect();
       if (r.top <= mid() && r.bottom > mid()) active = Number(sec.dataset.layer);
     });
-
     if (depthEl) depthEl.textContent = `${depthPrefix}${active}`;
 
     document.querySelectorAll('.stack-ruler button, .stack-ruler [data-goto], .tab-rail button, .tab[data-goto]').forEach((el) => {
@@ -34,21 +25,6 @@ export function initStackScroll(options = {}) {
       if (n === undefined) return;
       el.classList.toggle('active', Number(n) === active);
     });
-
-    sections.forEach((sec) => {
-      const layer = Number(sec.dataset.layer);
-      const panel = sec.querySelector(panelSelector);
-      if (!panel) return;
-
-      const r = sec.getBoundingClientRect();
-      const pr = panel.getBoundingClientRect();
-      const onStack = Math.abs(pr.top - rLine) < 10;
-      const past = r.bottom <= rLine;
-
-      sec.classList.toggle('is-active', layer === active);
-      sec.classList.toggle('is-stuck', onStack);
-      sec.classList.toggle('is-past', past);
-    });
   }
 
   document.querySelectorAll(tabSelector).forEach((tab) => {
@@ -63,6 +39,5 @@ export function initStackScroll(options = {}) {
   });
 
   window.addEventListener('scroll', updateDepth, { passive: true });
-  window.addEventListener('resize', updateDepth, { passive: true });
   updateDepth();
 }

shared/stack-vars.css

@@ -1,13 +1,12 @@
-/* Shared stack scroll — cards share one sticky line and cover via z-index */
+/* Sticky card stack — enough scroll per layer for cover effect */
 :root {
   --stack-nav: 2.5rem;
   --stack-stick: 3rem;
   --stack-step: 2.75rem;
-  --stack-tab-h: 2rem;
-  --stack-reveal: calc(var(--stack-stick) + var(--stack-step) * 6 + var(--stack-tab-h));
   --stack-slot: 100vh;
-  --stack-slot-last: 50vh;
-  /* Scroll one "deck" height before next card covers */
-  --stack-pull: calc(var(--stack-slot) - var(--stack-reveal));
-  --stack-body-h: calc(100dvh - var(--stack-reveal) - 1.25rem);
+  --stack-slot-last: 55vh;
+  /* ~70vh scroll per layer before the next card slides over */
+  --stack-scroll-step: 70vh;
+  --stack-pull: calc(var(--stack-slot) - var(--stack-scroll-step));
+  --stack-body-h: calc(100dvh - var(--stack-stick) - var(--stack-step) * 6 - 3rem);
 }