### Description The header does not stick to the top of the viewport. Tested in iOS Chrome, & iOS Safari. https://user-images.githubusercontent.com/3860311/119391948-0aae1400-bc9d-11eb-9f18-9e33c6cb352c.mov ### Reproduction Steps 1. Navigate to [this demo](https://000623720.deployed.codepen.website/) in iOS chrome 2. Open the CTA BUTTONS V2 story 3. Navigate to page 25 4. Swipe up or click the "About The Artist" CTA 5. Drag attachment up past top of viewport. Header should stick to top of viewport, instead it is scrolling beyond. ### Relevant Logs _No response_ ### Browser(s) Affected iOS Chrome iOS Safari ### AMP Version Affected 2105072136000 with experiment `amp-story-page-attachment-ui-v2` forced on in demo story.
Description
The header does not stick to the top of the viewport.
Tested in iOS Chrome, & iOS Safari.
RPReplay_Final1621880572.mov
Reproduction Steps
Header should stick to top of viewport, instead it is scrolling beyond.
Relevant Logs
No response
Browser(s) Affected
iOS Chrome
iOS Safari
AMP Version Affected
2105072136000 with experiment
amp-story-page-attachment-ui-v2forced on in demo story.