Fix overflow:hidden blocking scroll on html/body

The mita page (and others) have overflow:hidden on html and body,
which completely blocks programmatic scrolling. Now we override this
with overflow:auto !important in our injected CSS.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: MaxGhenis

scroll-utils.js

@@ -21,12 +21,19 @@ export function createSmoothScrollFunction(totalDistance) {
 export const SCROLL_OVERRIDE_ID = 'scrollywood-scroll-override';
 
 /**
- * Returns CSS that disables smooth scrolling to allow programmatic control.
- * This overrides scroll-behavior: smooth set in stylesheets, which can
- * conflict with window.scrollTo({ behavior: 'instant' }) in some browsers.
+ * Returns CSS that enables programmatic scrolling.
+ * - Disables scroll-behavior: smooth which conflicts with scrollTo()
+ * - Removes overflow: hidden which can block scrolling entirely
  */
 export function getScrollBehaviorOverrideCSS() {
-  return 'html, body, * { scroll-behavior: auto !important; }';
+  return `
+    html, body {
+      overflow: auto !important;
+      overflow-y: auto !important;
+      scroll-behavior: auto !important;
+    }
+    * { scroll-behavior: auto !important; }
+  `;
 }
 
 // Minimum scroll height threshold - anything below this is considered "not scrollable"

scroll-utils.test.js

@@ -55,6 +55,12 @@ describe('scroll-utils', () => {
       const css = getScrollBehaviorOverrideCSS();
       expect(css).toContain('*');
     });
+
+    it('should override overflow:hidden that blocks scrolling', () => {
+      const css = getScrollBehaviorOverrideCSS();
+      expect(css).toContain('overflow');
+      expect(css).toContain('auto');
+    });
   });
 
   describe('SCROLL_OVERRIDE_ID', () => {