[Bug]: Floorp Fluerial UI visible artifacts on fullscreen video

[noizo]

Pre-Submission Checklist

• [X] I have checked the existing/closed issues to ensure this issue has not already been reported.
• [X] I am using the latest supported version of the browser.
• [X] I have tried disabling all browser extensions/add-ons to rule out interference from these.
• [X] I have tried clearing the browser cache and cookies.
• [X] I have checked with a new profile and the issue still occurs.
• [X] I have provided detailed step-by-step instructions on how to reproduce the issue.
• [X] I have included relevant screenshots or console outputs.
• [X] I have checked that this problem is not occurring in the latest version of Firefox ESR.
• [X] This issue is specific to this browser and does not occur in other browsers.

Bug Summary

While watching full screen video on any website, there is a visible artifacts from UI theme. They are only visible while video is on full screen. I've marked places on a screenshot. It looks like it's due to corner rounding, which is also strange and visible only on upper left and lower right corners. Other corners looks ok. Also on bottom right there is a small strip, going through whole right side of screen.

This is not happening when PiP mode is enabled, only in browser video.

Reproduction Steps

Open any youtube video in full screen with Floorp Fluerial UI enabled.

Expected Behavior

Clean corners without artifacts

Actual Behavior

UI artifacts in full screen video.

Screenshots

Browser Version

v11.17.5

Operating System

MacOS Sonoma 14.6.1 (23G93)

Additional Context

No response