Prerequisites

• I have read the Contributing Guidelines.
• I agree to follow the Code of Conduct.
• I have searched for existing issues that already report this problem, without success.

Ionic Framework Version

v8.x

Current Behavior

I'm encountering an error related to adoptedStyleSheets in my Angular 18 and Ionic project. The console shows the following error:
TypeError: Failed to set the 'adoptedStyleSheets' property on 'Document': Failed to convert value to 'CSSStyleSheet'.

Expected Behavior

The application should run without any errors related to adoptedStyleSheets.

Steps to Reproduce

1. Clone the repository: git clone https://github.com/papastepano/try-ionic
2. Install dependencies: npm install
3. Run the development server: ng serve
4. Open the application in a browser and check the console for the error.

Code Reproduction URL

https://github.com/papastepano/try-ionic

Ionic Info

Ionic:

Ionic CLI : 7.2.0 (C:\Users\DELL\AppData\Roaming\npm\node_modules@ionic\cli)
Ionic Framework : @ionic/angular 8.2.1
@angular-devkit/build-angular : 18.0.3
@angular-devkit/schematics : 18.0.3
@angular/cli : 18.0.3
@ionic/angular-toolkit : 11.0.1

Utility:

cordova-res : not installed globally
native-run : not installed globally

System:

NodeJS : v20.11.0 (C:\Program Files\nodejs\node.exe)
npm : 10.4.0
OS : Windows 10

Additional Information

I suspect this might be due to browser compatibility or an issue with how CSSStyleSheet is being used in the project. Any insights or fixes would be appreciated.
Feel free to create a PR to the repo if you have a suggestion