CSS is stripped out because of the Content Security Policy in Jenkins.
The default rule is set to:
sandbox; default-src 'none'; img-src 'self'; style-src 'self';
This rule set results in the following:
- No plugins (object/embed) allowed
- No inline CSS, or CSS from other sites allowed
- No images from other sites allowed
- No frames allowed
- No web fonts allowed
- No XHR/AJAX allowed, etc.
To relax this rule, go to Manage Jenkins->Script console and type in the following command:
and Press Run. If you see the output as 'Result:' below "Result" header then the protection disabled. Re-Run your build and you can see that the new HTML files archived will have the CSS enabled.