Preflight Checklist

• I have read the Contributing Guidelines for this project.
• I agree to follow the Code of Conduct that this project adheres to.
• I have searched the issue tracker for a feature request that matches the one I want to file, without success.

Problem Description

Hello Electron team,

I'm experiencing an issue with the appearance of rounded corners in apps running on macOS 26, specifically when these apps are built with different versions of Xcode. I've attached a screenshot to illustrate the inconsistency:

Here's what I observed:

1. Visual Studio Code (built with Xcode 15): Rounded corners appear with a specific style.
2. Google Chrome (built with Xcode 16): Rounded corners have a different style.
3. Safari (built with Xcode 26): Displays yet another style of rounded corners.

This inconsistency might be due to changes or updates in the macOS SDKs across different versions of Xcode. Older Xcode versions might not fully support the visual updates introduced in macOS 26.

Proposed Solution

Could the Electron development team consider updating to the latest Xcode SDK to ensure consistent appearance and compatibility with macOS 26? This would help maintain a uniform look across applications and also take advantage of the latest improvements in macOS.

Thank you for your hard work and dedication.

Alternatives Considered

1. Manual Rebuild with Latest Xcode:
   I considered manually rebuilding the Electron app using the latest Xcode SDK on my own machine. However, this approach is not sustainable for all users and doesn't address the issue at scale.

2. Visual Adjustments via CSS or JavaScript:
   Another alternative was to implement custom CSS or JavaScript tweaks to adjust the UI elements. This method, however, could introduce additional maintenance challenges and doesn't fully utilize the system's native styles.