Google One Tap opens unusably small window for Safari when Privacy / Prevent cross-site tracking is enabled #9398

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Library Name

google-auth-library

A screenshot that you have tested with "Try this API".

Our website uses google-auth-library@11.1.0. When users with Safari (macOS) who have Privacy / Prevent cross-site tracking enabled navigate to our website and click the Continue button in the Google One Tap, a new window opens for them to select their user. This window is incorrectly sized and not centered on their screen.

If the Safari user has Privacy / Prevent cross-site tracking disabled, the problem does not occur.

Additionally, if they use the standard Sign in with Google button on our /login page, the problem does not occur.

Link to the code that reproduces this issue. A link to a public Github Repository or gist with a minimal reproduction.

https://www.schoolhouseyoga.com

A step-by-step description of how to reproduce the issue, based on the linked reproduction.

1. Set your macOS 26.x or 27.x computer's resolution to 1512 x 982 (MacBook Pro 14 default)
2. Using Safari 26 or 27, go to Settings -> Privacy and enabled "Prevent cross-site tracking".
3. Quit and re-launch Safari
4. Navigate to https://www.schoolhouseyoga.com
5. Click the Continue button in the Google One Tap area.
   Result: Undersized window will appear on the left (not centered). Size of window is not usable nor can it apparently be adjusted using code.

A clear and concise description of what the bug is, and what you expected to happen.

Clicking the Google One Tap Continue button opens an undersized window that is hard to use. Expected a window size similar to what is opened by the Sign in with Google button. I also expected it to be centered.

A clear and concise description WHY you expect this behavior, i.e., was it a recent change, there is documentation that points to this behavior, etc. **

I expect this behavior because the current window size is not usable. Users on Safari have to scroll the small window before any of the selections are usable.

We are probably going to drop Google One Tap until this is fixed.