Refused to apply inline style because it violates the following Content Security Policy directive: "default-src 'self'". Either the 'unsafe-inline' keyword, a hash ('sha256-/000000000000000000/00000000000000000000000='), or a nonce ('nonce-...') is required to enable inline execution. Note also that 'style-src' was not explicitly set, so 'default-src' is used as a fallback.

Attempt made to circumvent this policy by placing CSS Stylesheet inside HTML header . This was also blocked.

However, setting style inside element itself DOES work!
<div class="entry" style="background:yellow">

Disadvantage: This is too specific and makes the Userscript file larger.

TODO: Check SaxonJS. If SaxonJS won't do the task, go back to this issue.