diff --git a/public/cheatsheet.html b/public/cheatsheet.html
index 45996108f..9d60822e6 100644
--- a/public/cheatsheet.html
+++ b/public/cheatsheet.html
@@ -17,7 +17,8 @@
   <link rel="icon" type="image/svg+xml" href="./favicon.svg">
   <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=Instrument+Sans:wght@400;500;600&family=Space+Grotesk:wght@400;500;600&display=swap" rel="stylesheet">
+  <link href="https://fonts.googleapis.com/css2?family=Cormorant+Garamond:ital,wght@0,400;0,600;1,400&family=Instrument+Sans:wght@400;500;600&family=Space+Grotesk:wght@400;500;600&display=swap" rel="stylesheet">
+  <link rel="stylesheet" href="./css/sub-pages.css">
   <style>
     :root {
       --font-body: 'Instrument Sans', system-ui, sans-serif;
@@ -38,19 +39,25 @@
       }
     }
 
-    * { box-sizing: border-box; margin: 0; }
-
     body {
       font-family: var(--font-body);
       background: var(--color-paper);
       color: var(--color-ink);
       line-height: 1.5;
-      padding: 2rem;
-      max-width: 900px;
-      margin: 0 auto;
     }
 
-    header {
+    .cheatsheet-page-header,
+    main,
+    footer {
+      max-width: 900px;
+      margin-left: auto;
+      margin-right: auto;
+      padding-left: 2rem;
+      padding-right: 2rem;
+    }
+
+    .cheatsheet-page-header {
+      margin-top: 2rem;
       margin-bottom: 2rem;
       padding-bottom: 1.5rem;
       border-bottom: 1px solid var(--color-mist);
@@ -67,18 +74,6 @@
       font-size: 0.875rem;
     }
 
-    .back-link {
-      display: inline-block;
-      margin-top: 0.75rem;
-      font-size: 0.8125rem;
-      color: var(--color-accent);
-      text-decoration: none;
-    }
-
-    .back-link:hover {
-      text-decoration: underline;
-    }
-
     .category {
       margin-bottom: 2rem;
     }
@@ -152,8 +147,11 @@
     }
 
     @media print {
-      body { padding: 1rem; max-width: none; }
-      .back-link { display: none; }
+      body { padding: 1rem; }
+      .site-header { display: none; }
+      .cheatsheet-page-header,
+      main,
+      footer { max-width: none; padding-left: 0; padding-right: 0; }
       footer { display: none; }
       .command { page-break-inside: avoid; }
     }
@@ -166,12 +164,26 @@
     }
   </style>
 </head>
-<body>
-  <header>
+<body class="sub-page">
+  <!-- site-header v1 -->
+  <header class="site-header" data-site-header>
+    <a href="/" class="site-header-brand" aria-label="Impeccable home">
+      <span class="site-header-brand-name">Impeccable</span>
+    </a>
+    <nav class="site-header-nav" aria-label="Primary">
+      <a href="/" data-nav="home">Home</a>
+      <a href="/skills" data-nav="skills">Skills</a>
+      <a href="/anti-patterns" data-nav="anti-patterns">Anti-Patterns</a>
+      <a href="/tutorials" data-nav="tutorials">Tutorials</a>
+      <a href="/gallery" data-nav="gallery">Gallery</a>
+      <a href="https://github.com/pbakaus/impeccable" target="_blank" rel="noopener" data-nav="github">GitHub</a>
+    </nav>
+  </header>
+
+  <div class="cheatsheet-page-header">
     <h1>Impeccable Commands</h1>
     <p class="subtitle">Quick reference for all 21 design commands</p>
-    <a href="/" class="back-link">&larr; Back to impeccable.style</a>
-  </header>
+  </div>
 
   <main id="commands-container">
     <p style="color: var(--color-ash);">Loading commands...</p>
diff --git a/public/gallery.html b/public/gallery.html
index 30acf83de..c2fcc61e4 100644
--- a/public/gallery.html
+++ b/public/gallery.html
@@ -16,6 +16,7 @@
   <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=Cormorant+Garamond:ital,wght@0,400;0,600;1,400;1,600&family=Instrument+Sans:wght@400;500;600&family=Space+Grotesk:wght@400;500;600&display=swap" rel="stylesheet">
+  <link rel="stylesheet" href="./css/sub-pages.css">
   <style>
     :root {
       --font-display: 'Cormorant Garamond', Georgia, serif;
@@ -50,28 +51,8 @@
       -webkit-font-smoothing: antialiased;
     }
 
-    a { color: var(--color-accent); text-decoration: underline; text-underline-offset: 3px; }
-    a:hover { color: var(--color-accent-hover); }
-
-    /* Header */
-    .site-header {
-      padding: var(--spacing-sm) var(--spacing-lg);
-      border-bottom: 1px solid var(--color-mist);
-      display: flex;
-      align-items: center;
-      justify-content: space-between;
-    }
-    .site-header a { text-decoration: none; }
-    .header-brand {
-      font-family: var(--font-display);
-      font-size: 1.25rem;
-      font-weight: 600;
-      font-style: italic;
-      color: var(--color-ink);
-    }
-    .header-nav { display: flex; gap: var(--spacing-md); font-size: 0.875rem; }
-    .header-nav a { color: var(--color-ash); }
-    .header-nav a:hover { color: var(--color-ink); }
+    .gallery-content a { color: var(--color-accent); text-decoration: underline; text-underline-offset: 3px; }
+    .gallery-content a:hover { color: var(--color-accent-hover); }
 
     /* Hero */
     .hero {
@@ -201,19 +182,23 @@
         grid-template-columns: 1fr;
         padding: 0 var(--spacing-sm) var(--spacing-lg);
       }
-      .site-header { padding: var(--spacing-sm); }
-      .header-nav { gap: var(--spacing-sm); }
     }
   </style>
 </head>
-<body>
+<body class="sub-page gallery-content">
 
-  <header class="site-header">
-    <a href="/" class="header-brand">Impeccable</a>
-    <nav class="header-nav">
-      <a href="/#antidote">Anti-Patterns</a>
-      <a href="/cheatsheet">Cheatsheet</a>
-      <a href="https://github.com/pbakaus/impeccable">GitHub</a>
+  <!-- site-header v1 -->
+  <header class="site-header" data-site-header>
+    <a href="/" class="site-header-brand" aria-label="Impeccable home">
+      <span class="site-header-brand-name">Impeccable</span>
+    </a>
+    <nav class="site-header-nav" aria-label="Primary">
+      <a href="/" data-nav="home">Home</a>
+      <a href="/skills" data-nav="skills">Skills</a>
+      <a href="/anti-patterns" data-nav="anti-patterns">Anti-Patterns</a>
+      <a href="/tutorials" data-nav="tutorials">Tutorials</a>
+      <a href="/gallery" data-nav="gallery" aria-current="page">Gallery</a>
+      <a href="https://github.com/pbakaus/impeccable" target="_blank" rel="noopener" data-nav="github">GitHub</a>
     </nav>
   </header>
 
diff --git a/public/index.html b/public/index.html
index 666d63681..c75846492 100644
--- a/public/index.html
+++ b/public/index.html
@@ -38,7 +38,8 @@
   <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
   <link href="https://fonts.googleapis.com/css2?family=Cormorant+Garamond:ital,wght@0,300;0,400;0,600;0,700;1,300;1,400&family=Instrument+Sans:wght@400;500;600;700&family=Inter:wght@400;500;600&family=Space+Grotesk:wght@400;500;600&display=swap" rel="stylesheet">
   <link rel="stylesheet" href="./css/main.css">
-  
+  <link rel="stylesheet" href="./css/sub-pages.css">
+
   </head>
 <body>
   <!-- Skip to main content link for keyboard users -->
@@ -47,6 +48,21 @@
   <!-- Grain Overlay -->
   <div class="grain-overlay" aria-hidden="true"></div>
 
+  <!-- site-header v1 -->
+  <header class="site-header" data-site-header>
+    <a href="/" class="site-header-brand" aria-label="Impeccable home">
+      <span class="site-header-brand-name">Impeccable</span>
+    </a>
+    <nav class="site-header-nav" aria-label="Primary">
+      <a href="/" data-nav="home" aria-current="page">Home</a>
+      <a href="/skills" data-nav="skills">Skills</a>
+      <a href="/anti-patterns" data-nav="anti-patterns">Anti-Patterns</a>
+      <a href="/tutorials" data-nav="tutorials">Tutorials</a>
+      <a href="/gallery" data-nav="gallery">Gallery</a>
+      <a href="https://github.com/pbakaus/impeccable" target="_blank" rel="noopener" data-nav="github">GitHub</a>
+    </nav>
+  </header>
+
   <!-- Sticky Section Nav -->
   <nav class="section-nav" id="section-nav" aria-label="Page sections">
     <a href="#foundation" class="section-nav-item" data-section="foundation"><span class="section-nav-num">01</span><span class="section-nav-label">Foundation</span></a>
diff --git a/public/privacy.html b/public/privacy.html
index 6109c4694..7785d5fdc 100644
--- a/public/privacy.html
+++ b/public/privacy.html
@@ -6,17 +6,39 @@
   <title>Privacy Policy - Impeccable</title>
   <meta name="robots" content="noindex">
   <link rel="icon" type="image/svg+xml" href="./favicon.svg">
+  <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=Cormorant+Garamond:ital,wght@0,400;0,600&family=Instrument+Sans:wght@400;500;600&family=Space+Grotesk:wght@400;500;600&display=swap" rel="stylesheet">
+  <link rel="stylesheet" href="./css/sub-pages.css">
   <style>
-    body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; max-width: 680px; margin: 0 auto; padding: 2rem 1.5rem; line-height: 1.6; color: #1a1a1a; }
-    h1 { font-size: 1.8rem; margin-bottom: 0.5rem; }
-    h2 { font-size: 1.2rem; margin-top: 2rem; }
-    .updated { color: #666; font-size: 0.9rem; margin-bottom: 2rem; }
-    a { color: #1a1a1a; }
-    .back { display: inline-block; margin-bottom: 2rem; font-size: 0.9rem; }
+    .privacy-content { max-width: 680px; margin: 0 auto; padding: 2rem 1.5rem 4rem; }
+    .privacy-content h1 { font-family: var(--font-display); font-size: 2.25rem; margin-bottom: 0.5rem; letter-spacing: -0.01em; }
+    .privacy-content h2 { font-size: 1.125rem; margin-top: 2rem; font-weight: 600; }
+    .privacy-content p, .privacy-content ul { color: var(--color-charcoal); margin-top: 0.5rem; }
+    .privacy-content ul { padding-left: 1.25rem; }
+    .privacy-content li { margin-top: 0.25rem; }
+    .privacy-content a { color: var(--color-accent); text-decoration: underline; text-underline-offset: 3px; }
+    .privacy-content a:hover { color: var(--color-accent-hover); }
+    .privacy-content .updated { color: var(--color-ash); font-size: 0.875rem; margin-bottom: 2rem; font-style: italic; }
   </style>
 </head>
-<body>
-  <a href="/" class="back">&larr; Back to impeccable.style</a>
+<body class="sub-page">
+  <!-- site-header v1 -->
+  <header class="site-header" data-site-header>
+    <a href="/" class="site-header-brand" aria-label="Impeccable home">
+      <span class="site-header-brand-name">Impeccable</span>
+    </a>
+    <nav class="site-header-nav" aria-label="Primary">
+      <a href="/" data-nav="home">Home</a>
+      <a href="/skills" data-nav="skills">Skills</a>
+      <a href="/anti-patterns" data-nav="anti-patterns">Anti-Patterns</a>
+      <a href="/tutorials" data-nav="tutorials">Tutorials</a>
+      <a href="/gallery" data-nav="gallery">Gallery</a>
+      <a href="https://github.com/pbakaus/impeccable" target="_blank" rel="noopener" data-nav="github">GitHub</a>
+    </nav>
+  </header>
+
+  <main class="privacy-content">
   <h1>Privacy Policy</h1>
   <p class="updated">Last updated: April 6, 2026</p>
 
@@ -48,5 +70,6 @@
 
   <h2>Contact</h2>
   <p>Questions about this policy? Open an issue on <a href="https://github.com/pbakaus/impeccable">GitHub</a> or reach out to <a href="https://x.com/pbakaus">@pbakaus</a>.</p>
+  </main>
 </body>
 </html>
diff --git a/scripts/build.js b/scripts/build.js
index f74a85f23..8cc4756f8 100644
--- a/scripts/build.js
+++ b/scripts/build.js
@@ -158,6 +158,40 @@ function validateAntipatternRules(rootDir) {
   return errors;
 }
 
+/**
+ * Validate that every hand-authored HTML page carries the shared site header.
+ * The partial is stamped with `<!-- site-header v1 -->` so drift is loud.
+ *
+ * Returns the number of validation errors. Build fails if > 0.
+ */
+function validateSiteHeader(rootDir) {
+  const pages = [
+    'public/index.html',
+    'public/cheatsheet.html',
+    'public/gallery.html',
+    'public/privacy.html',
+  ];
+  const marker = '<!-- site-header v1 -->';
+  let errors = 0;
+  for (const rel of pages) {
+    const full = path.join(rootDir, rel);
+    if (!fs.existsSync(full)) {
+      console.error(`  ❌ ${rel} is missing`);
+      errors++;
+      continue;
+    }
+    const src = fs.readFileSync(full, 'utf-8');
+    if (!src.includes(marker)) {
+      console.error(`  ❌ ${rel} is missing the shared site header marker '${marker}'`);
+      errors++;
+    }
+  }
+  if (errors === 0) {
+    console.log(`✓ Validated site header on ${pages.length} hand-authored pages`);
+  }
+  return errors;
+}
+
 /**
  * Copy directory recursively
  */
@@ -478,7 +512,11 @@ async function build() {
 
   // Cross-validate engine rules against impeccable SKILL.md DON'Ts
   const validationErrors = validateAntipatternRules(ROOT_DIR);
-  if (countErrors > 0 || validationErrors > 0) {
+
+  // Verify every hand-authored HTML page carries the shared site header
+  const headerErrors = validateSiteHeader(ROOT_DIR);
+
+  if (countErrors > 0 || validationErrors > 0 || headerErrors > 0) {
     process.exit(1);
   }
 
diff --git a/server/index.js b/server/index.js
index 2d21f6244..8c023434f 100644
--- a/server/index.js
+++ b/server/index.js
@@ -2,6 +2,7 @@ import { serve, file } from "bun";
 import homepage from "../public/index.html";
 import cheatsheet from "../public/cheatsheet.html";
 import gallery from "../public/gallery.html";
+import privacy from "../public/privacy.html";
 import {
   getSkills,
   getCommands,
@@ -18,6 +19,7 @@ const server = serve({
     "/": homepage,
     "/cheatsheet": cheatsheet,
     "/gallery": gallery,
+    "/privacy": privacy,
 
     // Static assets - all public subdirectories
     "/assets/*": async (req) => {
