diff --git a/README.md b/README.md
index 010d531..ed2f52e 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # levkin.ca
 
-Four design concepts for the Levkin software development company homepage.
+Five design concepts for the Levkin software development company homepage.
 
 | Option | Path | Vibe |
 |--------|------|------|
@@ -8,8 +8,9 @@ Four design concepts for the Levkin software development company homepage.
 | **Slab** | `/slab/` | Brutalist poster, massive typography |
 | **Relay** | `/relay/` | Telegraph, signal chain, decoded messages |
 | **Vault** | `/vault/` | Institutional trust, enterprise gravitas |
+| **Stack** | `/stack/` | Sticky scroll layers L0–L6, services as a card stack |
 
-Open `/` to compare all four.
+Open `/` to compare all five.
 
 ## Develop
 
diff --git a/index.html b/index.html
index fcd628e..6466490 100644
--- a/index.html
+++ b/index.html
@@ -48,8 +48,11 @@
     @media (min-width: 640px) {
       .grid { grid-template-columns: repeat(2, 1fr); }
     }
-    @media (min-width: 960px) {
-      .grid { grid-template-columns: repeat(4, 1fr); }
+    @media (min-width: 900px) {
+      .grid { grid-template-columns: repeat(3, 1fr); }
+    }
+    @media (min-width: 1200px) {
+      .grid { grid-template-columns: repeat(5, 1fr); }
     }
     a.card {
       display: block;
@@ -108,6 +111,25 @@
       letter-spacing: 0.25em;
       text-transform: uppercase;
     }
+    .preview--stack {
+      background: #0e0e10;
+      flex-direction: column;
+      gap: 4px;
+      padding: 1.5rem;
+    }
+    .preview--stack .card-layer {
+      width: 70%;
+      height: 14px;
+      border-radius: 3px;
+      border: 1px solid rgba(255,255,255,0.1);
+      background: linear-gradient(90deg, #2a2a32, #3a3a46);
+      box-shadow: 0 2px 8px rgba(0,0,0,0.4);
+    }
+    .preview--stack .card-layer:nth-child(1) { width: 55%; opacity: 0.5; }
+    .preview--stack .card-layer:nth-child(2) { width: 62%; opacity: 0.65; }
+    .preview--stack .card-layer:nth-child(3) { width: 68%; opacity: 0.8; }
+    .preview--stack .card-layer:nth-child(4) { width: 75%; }
+    .preview--stack .card-layer:nth-child(5) { width: 82%; background: #4a4a58; }
     .card-body { padding: 1.15rem 1.25rem 1.35rem; }
     .card-body h2 { font-size: 1.05rem; font-weight: 600; margin-bottom: 0.3rem; }
     .card-body p { font-size: 0.82rem; color: var(--muted); line-height: 1.4; }
@@ -141,8 +163,8 @@
   <div class="wrap">
     <header>
       <p class="eyebrow">levkin.ca · round 3</p>
-      <h1>Four directions.</h1>
-      <p class="lead">Enriched from auto, caseware, iliadobkin, and jobs — proof points, stacks, clients, and booking. Company-first throughout.</p>
+      <h1>Five directions.</h1>
+      <p class="lead">Enriched from auto, caseware, iliadobkin, and jobs — plus Stack: scroll the layers. Company-first throughout.</p>
     </header>
 
     <div class="grid">
@@ -181,6 +203,21 @@
           <span class="tag">trust · enterprise · calm</span>
         </div>
       </a>
+
+      <a class="card" href="/stack/">
+        <div class="preview preview--stack">
+          <span class="card-layer"></span>
+          <span class="card-layer"></span>
+          <span class="card-layer"></span>
+          <span class="card-layer"></span>
+          <span class="card-layer"></span>
+        </div>
+        <div class="card-body">
+          <h2>Stack</h2>
+          <p>Scroll through layers — L0 foundation to L6 interface. Services as a literal stack of cards.</p>
+          <span class="tag">layers · scroll · architectural</span>
+        </div>
+      </a>
     </div>
 
     <footer>
diff --git a/stack/index.html b/stack/index.html
new file mode 100644
index 0000000..4a59c9b
--- /dev/null
+++ b/stack/index.html
@@ -0,0 +1,143 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8" />
+  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  <title>Levkin — Stack</title>
+  <meta name="description" content="Levkin — software development, layer by layer." />
+  <link rel="icon" href="/favicon.svg" type="image/svg+xml" />
+  <link rel="preconnect" href="https://fonts.googleapis.com" />
+  <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />
+  <link href="https://fonts.googleapis.com/css2?family=IBM+Plex+Mono:wght@400;500;600&family=Instrument+Sans:wght@400;500;600&display=swap" rel="stylesheet" />
+  <link rel="stylesheet" href="./stack.css" />
+</head>
+<body>
+  <nav class="nav">
+    <a href="/">← options</a>
+    <span class="depth" id="depth">depth: 0</span>
+  </nav>
+
+  <div class="stack-viewport">
+    <!-- L0 — foundation -->
+    <section class="layer layer-0" data-layer="0">
+      <div class="layer-inner">
+        <header class="layer-head">
+          <span class="layer-id">L0</span>
+          <span class="layer-name">foundation</span>
+        </header>
+        <h1>Levkin</h1>
+        <p class="tagline">Software development · Canada · remote</p>
+        <p class="body">A boutique engineering practice — production systems, automation, and enterprise tooling. Not a body shop. Fixed scope, documented handoff, optional stewardship.</p>
+        <div class="chips">
+          <span>15+ years</span>
+          <span>8h → &lt;2min releases</span>
+          <span>24/7 automation</span>
+        </div>
+        <p class="avail">Currently taking on new engagements</p>
+      </div>
+    </section>
+
+    <!-- L1 — custom -->
+    <section class="layer layer-1" data-layer="1">
+      <div class="layer-inner">
+        <header class="layer-head">
+          <span class="layer-id">L1</span>
+          <span class="layer-name">application</span>
+        </header>
+        <h2>Custom software</h2>
+        <p class="body">Web apps, APIs, internal tools. Stack-agnostic — boring, proven tech preferred.</p>
+        <ul class="stack-list">
+          <li>TypeScript / Node · Python · C# / .NET</li>
+          <li>PostgreSQL · SQL Server · React · Vue</li>
+        </ul>
+      </div>
+    </section>
+
+    <!-- L2 — automation -->
+    <section class="layer layer-2" data-layer="2">
+      <div class="layer-inner">
+        <header class="layer-head">
+          <span class="layer-id">L2</span>
+          <span class="layer-name">automation</span>
+          <a href="https://auto.levkin.ca" class="layer-link">auto.levkin.ca ↗</a>
+        </header>
+        <h2>Automation</h2>
+        <p class="body">Scripts, no-code workflows, CI/CD, webhooks, LLM integrations — runs while you sleep.</p>
+        <ul class="stack-list">
+          <li>n8n · Zapier · Make · GitHub Actions</li>
+          <li>Jenkins · Azure DevOps · Python · Bash</li>
+        </ul>
+      </div>
+    </section>
+
+    <!-- L3 — caseware -->
+    <section class="layer layer-3" data-layer="3">
+      <div class="layer-inner">
+        <header class="layer-head">
+          <span class="layer-id">L3</span>
+          <span class="layer-name">enterprise</span>
+          <a href="https://caseware.levkin.ca" class="layer-link">caseware.levkin.ca ↗</a>
+        </header>
+        <h2>CaseWare &amp; CaseView</h2>
+        <p class="body">Features, templates, release automation for audit &amp; accounting. CaseWare International, MNP, JazzIt.</p>
+        <ul class="stack-list">
+          <li>C# · .NET · SQL Server · JavaScript CI</li>
+        </ul>
+      </div>
+    </section>
+
+    <!-- L4 — QE -->
+    <section class="layer layer-4" data-layer="4">
+      <div class="layer-inner">
+        <header class="layer-head">
+          <span class="layer-id">L4</span>
+          <span class="layer-name">quality</span>
+          <a href="https://iliadobkin.com" class="layer-link">iliadobkin.com ↗</a>
+        </header>
+        <h2>Quality engineering</h2>
+        <p class="body">Senior SDET — test automation, CI/CD, trace-driven debugging.</p>
+      </div>
+    </section>
+
+    <!-- L5 — ops -->
+    <section class="layer layer-5" data-layer="5">
+      <div class="layer-inner">
+        <header class="layer-head">
+          <span class="layer-id">L5</span>
+          <span class="layer-name">operations</span>
+          <a href="https://jobs.levkin.ca" class="layer-link">jobs.levkin.ca ↗</a>
+        </header>
+        <h2>Job Ops</h2>
+        <p class="body">Internal hiring orchestrator — authenticated, per-user job lists.</p>
+      </div>
+    </section>
+
+    <!-- L6 — surface / contact -->
+    <section class="layer layer-6" data-layer="6">
+      <div class="layer-inner">
+        <header class="layer-head">
+          <span class="layer-id">L6</span>
+          <span class="layer-name">interface</span>
+        </header>
+        <h2>Engage</h2>
+        <p class="body">Discover → Proposal → Ship → Maintain (optional). Fixed-scope quotes after a 15-minute call.</p>
+        <div class="contact-row">
+          <a class="btn" href="https://cal.levkin.ca/ilia/consult">Book 15 min →</a>
+          <a class="btn btn-ghost" href="mailto:hello@levkine.ca?subject=Stack%20enquiry">hello@levkine.ca</a>
+        </div>
+        <p class="guarantees">Retries · docs · tests before prod · smallest solution that fits</p>
+        <footer class="layer-foot">
+          <a href="https://git.levkin.ca">git.levkin.ca</a>
+          <span>levkin.ca</span>
+        </footer>
+      </div>
+    </section>
+  </div>
+
+  <div class="stack-ruler" aria-hidden="true">
+    <span>L0</span><span>L1</span><span>L2</span><span>L3</span><span>L4</span><span>L5</span><span>L6</span>
+  </div>
+
+  <script src="./stack.js" type="module"></script>
+</body>
+</html>
diff --git a/stack/stack.css b/stack/stack.css
new file mode 100644
index 0000000..84df88c
--- /dev/null
+++ b/stack/stack.css
@@ -0,0 +1,280 @@
+:root {
+  --bg: #0e0e10;
+  --mono: 'IBM Plex Mono', ui-monospace, monospace;
+  --sans: 'Instrument Sans', system-ui, sans-serif;
+  --sticky-top: 3.5rem;
+  --layer-offset: 2.75rem;
+}
+
+* { box-sizing: border-box; margin: 0; padding: 0; }
+
+html { scroll-behavior: smooth; }
+
+body {
+  font-family: var(--sans);
+  background: var(--bg);
+  color: #e8e6e3;
+  line-height: 1.55;
+  overflow-x: hidden;
+}
+
+.nav {
+  position: fixed;
+  top: 0;
+  left: 0;
+  right: 0;
+  z-index: 100;
+  display: flex;
+  justify-content: space-between;
+  padding: 1rem 1.5rem;
+  font-family: var(--mono);
+  font-size: 0.72rem;
+  background: rgba(14, 14, 16, 0.85);
+  backdrop-filter: blur(8px);
+  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
+}
+
+.nav a {
+  color: #6b6966;
+  text-decoration: none;
+}
+
+.nav a:hover { color: #c4a574; }
+
+.depth {
+  color: #6b6966;
+  font-variant-numeric: tabular-nums;
+}
+
+.stack-viewport {
+  padding: 0 1.5rem 8rem;
+  max-width: 640px;
+  margin: 0 auto;
+}
+
+/* Sticky card stack — each layer sticks, next slides over */
+.layer {
+  position: sticky;
+  min-height: 72vh;
+  margin-bottom: 1.5rem;
+  border-radius: 12px;
+  border: 1px solid rgba(255, 255, 255, 0.08);
+  box-shadow:
+    0 -1px 0 rgba(255, 255, 255, 0.05) inset,
+    0 24px 48px rgba(0, 0, 0, 0.45),
+    0 4px 12px rgba(0, 0, 0, 0.3);
+  transform-origin: center top;
+  transition: transform 0.15s ease-out;
+}
+
+.layer-0 { top: var(--sticky-top); z-index: 1; background: #1a1a1e; }
+.layer-1 { top: calc(var(--sticky-top) + var(--layer-offset) * 1); z-index: 2; background: #222228; }
+.layer-2 { top: calc(var(--sticky-top) + var(--layer-offset) * 2); z-index: 3; background: #2a2a32; }
+.layer-3 { top: calc(var(--sticky-top) + var(--layer-offset) * 3); z-index: 4; background: #32323c; }
+.layer-4 { top: calc(var(--sticky-top) + var(--layer-offset) * 4); z-index: 5; background: #3a3a46; }
+.layer-5 { top: calc(var(--sticky-top) + var(--layer-offset) * 5); z-index: 6; background: #42424e; }
+.layer-6 { top: calc(var(--sticky-top) + var(--layer-offset) * 6); z-index: 7; background: #4a4a58; margin-bottom: 4rem; }
+
+.layer-inner {
+  padding: 2rem 2rem 2.5rem;
+}
+
+.layer-head {
+  display: flex;
+  flex-wrap: wrap;
+  align-items: center;
+  gap: 0.5rem 1rem;
+  margin-bottom: 1.25rem;
+  padding-bottom: 0.75rem;
+  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
+  font-family: var(--mono);
+  font-size: 0.7rem;
+}
+
+.layer-id {
+  color: #c4a574;
+  font-weight: 600;
+  letter-spacing: 0.08em;
+}
+
+.layer-name {
+  color: #6b6966;
+  text-transform: uppercase;
+  letter-spacing: 0.12em;
+}
+
+.layer-link {
+  margin-left: auto;
+  color: #8b9cb3;
+  text-decoration: none;
+  font-size: 0.65rem;
+}
+
+.layer-link:hover { color: #c4a574; }
+
+.layer h1 {
+  font-size: clamp(2.5rem, 10vw, 3.5rem);
+  font-weight: 600;
+  letter-spacing: -0.04em;
+  margin-bottom: 0.35rem;
+}
+
+.layer h2 {
+  font-size: 1.75rem;
+  font-weight: 600;
+  letter-spacing: -0.03em;
+  margin-bottom: 0.5rem;
+}
+
+.tagline {
+  font-family: var(--mono);
+  font-size: 0.8rem;
+  color: #6b6966;
+  letter-spacing: 0.06em;
+  margin-bottom: 1rem;
+}
+
+.body {
+  color: #a8a6a1;
+  font-size: 1rem;
+  max-width: 38ch;
+  margin-bottom: 1rem;
+}
+
+.chips {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.5rem;
+  margin-bottom: 1rem;
+}
+
+.chips span {
+  font-family: var(--mono);
+  font-size: 0.65rem;
+  padding: 0.3rem 0.55rem;
+  background: rgba(196, 165, 116, 0.12);
+  color: #c4a574;
+  border: 1px solid rgba(196, 165, 116, 0.25);
+  border-radius: 4px;
+}
+
+.avail {
+  font-family: var(--mono);
+  font-size: 0.72rem;
+  color: #7eb87a;
+  letter-spacing: 0.04em;
+}
+
+.stack-list {
+  list-style: none;
+  font-family: var(--mono);
+  font-size: 0.78rem;
+  color: #6b6966;
+  line-height: 1.7;
+}
+
+.contact-row {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.75rem;
+  margin: 1.25rem 0;
+}
+
+.btn {
+  font-family: var(--mono);
+  font-size: 0.8rem;
+  padding: 0.65rem 1.1rem;
+  background: #c4a574;
+  color: #0e0e10;
+  text-decoration: none;
+  font-weight: 600;
+  border-radius: 6px;
+  transition: background 0.15s, color 0.15s;
+}
+
+.btn:hover {
+  background: #e8d4b0;
+}
+
+.btn-ghost {
+  background: transparent;
+  color: #c4a574;
+  border: 1px solid rgba(196, 165, 116, 0.4);
+}
+
+.btn-ghost:hover {
+  background: rgba(196, 165, 116, 0.1);
+  color: #e8d4b0;
+}
+
+.guarantees {
+  font-family: var(--mono);
+  font-size: 0.68rem;
+  color: #6b6966;
+  letter-spacing: 0.02em;
+}
+
+.layer-foot {
+  display: flex;
+  justify-content: space-between;
+  margin-top: 2rem;
+  padding-top: 1rem;
+  border-top: 1px solid rgba(255, 255, 255, 0.08);
+  font-family: var(--mono);
+  font-size: 0.65rem;
+  color: #6b6966;
+}
+
+.layer-foot a {
+  color: #6b6966;
+  text-decoration: none;
+}
+
+.layer-foot a:hover { color: #c4a574; }
+
+/* Side ruler — stack depth indicator */
+.stack-ruler {
+  position: fixed;
+  right: 1.25rem;
+  top: 50%;
+  transform: translateY(-50%);
+  z-index: 50;
+  display: flex;
+  flex-direction: column;
+  gap: 0.35rem;
+  font-family: var(--mono);
+  font-size: 0.55rem;
+  color: #3a3a40;
+  letter-spacing: 0.06em;
+  pointer-events: none;
+}
+
+.stack-ruler span {
+  padding: 0.15rem 0;
+  transition: color 0.2s, transform 0.2s;
+}
+
+.stack-ruler span.active {
+  color: #c4a574;
+  transform: translateX(-4px);
+}
+
+@media (max-width: 700px) {
+  .stack-ruler { display: none; }
+  :root { --layer-offset: 1.75rem; }
+  .layer { min-height: 65vh; }
+  .layer-inner { padding: 1.5rem 1.25rem 2rem; }
+}
+
+/* Subtle edge highlight — “card” lip */
+.layer::before {
+  content: '';
+  position: absolute;
+  top: 0;
+  left: 0;
+  right: 0;
+  height: 3px;
+  border-radius: 12px 12px 0 0;
+  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.12), transparent);
+  pointer-events: none;
+}
diff --git a/stack/stack.js b/stack/stack.js
new file mode 100644
index 0000000..16f1ee8
--- /dev/null
+++ b/stack/stack.js
@@ -0,0 +1,24 @@
+const layers = document.querySelectorAll('.layer');
+const depthEl = document.getElementById('depth');
+const rulerSpans = document.querySelectorAll('.stack-ruler span');
+
+function updateDepth() {
+  const mid = window.innerHeight * 0.45;
+  let active = 0;
+
+  layers.forEach((layer) => {
+    const rect = layer.getBoundingClientRect();
+    if (rect.top <= mid && rect.bottom > mid) {
+      active = Number(layer.dataset.layer);
+    }
+  });
+
+  depthEl.textContent = `depth: L${active}`;
+
+  rulerSpans.forEach((span, i) => {
+    span.classList.toggle('active', i === active);
+  });
+}
+
+window.addEventListener('scroll', updateDepth, { passive: true });
+updateDepth();
diff --git a/vite.config.js b/vite.config.js
index 04951e7..cb71672 100644
--- a/vite.config.js
+++ b/vite.config.js
@@ -10,6 +10,7 @@ export default defineConfig({
         slab: resolve(__dirname, 'slab/index.html'),
         relay: resolve(__dirname, 'relay/index.html'),
         vault: resolve(__dirname, 'vault/index.html'),
+        stack: resolve(__dirname, 'stack/index.html'),
       },
     },
   },
