[BUG] claude.ai/design canvas: no scrolling on mobile Safari; scroll hard-stops partway on desktop

Summary

The claude.ai/design canvas cannot be scrolled on mobile Safari (iOS). The canvas view loads but does not respond to touch scrolling, making designs unviewable on mobile.

Additionally, the same canvas has a reproducible scroll limitation on desktop: programmatic and manual scrolling (wheel, keyboard Page Down, drag) consistently stops at a fixed position partway down a long design document and cannot go further. Reproduced across zoom levels (50% / 100%) and after fresh reloads.

Environment

• Mobile: Safari on iOS — canvas does not scroll at all
• Desktop: Chrome (macOS, Darwin 23.6) — canvas scroll hard-stops at a fixed position on long documents (reproduced repeatedly during browser automation via the Claude in Chrome extension; multiple input methods tried: mouse wheel, keyboard, drag, fullscreen reload)
• Product: claude.ai/design (Claude Design), project canvas view with a long single-file design document (~80KB .dc.html, two artboards side by side)

Steps to reproduce

1. Create a claude.ai/design project with a long design file (e.g. a full landing page mockup with mobile + desktop artboards).
2. Open the project canvas on mobile Safari → touch scrolling does not move the canvas.
3. On desktop Chrome, scroll down the canvas → scrolling stops at a fixed position before the end of the document and no input method can scroll past it.

Workaround

Present (preview) mode scrolls normally as a regular page on both desktop and mobile — only the canvas view is affected.

Expected

Canvas view should be scrollable (or pannable) to the full extent of the document on both desktop and mobile browsers.