diff --git a/craft/src/utils/html-export.test.ts b/craft/src/utils/html-export.test.ts
index 07294e2..a07c09d 100644
--- a/craft/src/utils/html-export.test.ts
+++ b/craft/src/utils/html-export.test.ts
@@ -404,6 +404,22 @@ describe('buildAnimationScript (animation fix)', () => {
   test('returns empty string when body has no data-animation', () => {
     expect(buildAnimationScript('<div>Hi</div>')).toBe('');
   });
+
+  test('reveal script coerces a bare-number delay to a valid CSS time (e.g. "2" -> "2s")', () => {
+    // animationDelay is stored as a plain seconds string ("2"); assigning that raw
+    // to el.style.animationDelay is invalid CSS and no-ops. The script must suffix a
+    // unit onto bare numbers while leaving unit-bearing values ("2s"/"200ms") alone.
+    const script = buildAnimationScript('<div data-animation="fade-in" data-animation-delay="2">Hi</div>');
+    expect(script).toContain("/^-?[0-9.]+$/.test(delay) ? delay + 's' : delay");
+    // guard against regressing to the raw (invalid) assignment
+    expect(script).not.toContain('animationDelay = delay;');
+    // sanity-check the coercion logic itself against representative inputs
+    const coerce = (delay: string) => (/^-?[0-9.]+$/.test(delay) ? delay + 's' : delay);
+    expect(coerce('2')).toBe('2s');
+    expect(coerce('0.5')).toBe('0.5s');
+    expect(coerce('2s')).toBe('2s');
+    expect(coerce('200ms')).toBe('200ms');
+  });
 });
 
 describe('Preview body-replacement keeps exactly one reveal script (animation fix)', () => {
diff --git a/craft/src/utils/html-export.ts b/craft/src/utils/html-export.ts
index 07df8ab..83588fd 100644
--- a/craft/src/utils/html-export.ts
+++ b/craft/src/utils/html-export.ts
@@ -354,7 +354,7 @@ const ANIMATION_CSS_MINIFIED = `@keyframes fadeIn{from{opacity:0}to{opacity:1}}@
 const ANIMATION_SCRIPT = `<script>
 document.querySelectorAll('[data-animation]').forEach(function(el) {
   var delay = el.getAttribute('data-animation-delay');
-  if (delay) el.style.animationDelay = delay;
+  if (delay) el.style.animationDelay = /^-?[0-9.]+$/.test(delay) ? delay + 's' : delay;
   new IntersectionObserver(function(entries) {
     entries.forEach(function(e) { if (e.isIntersecting) { el.classList.add('animated'); } });
   }, { threshold: 0.1 }).observe(el);