I am struggling to get custom CSS to work in WordPress. I am using version 6.1.1.

I want to turn off underlining of the link in the site title when you hover over it. I am using a Twenty-twenty three theme. I have attempted this by setting a custom class on the site title block (site_banner), and then added the following CSS to style.css:

.site_banner a:hover {
   text-decoration: none;
}

Either this stylesheet is not being included, or it is being overridden somewhere. I’m not sure how/where I am supposed to put my code, or how to debug the problem. I can’t find anything about custom CSS in the WordPress documentation, other than altering site global themes. A few tutorials I have found have told me that what I am doing should work. And it has in previous versions of WordPress.

Any help is appreciated.