Missing stylesheet after moving WordPress to new directory

Can anyone tell me where to look for the problem when, after moving wordpress to its own directory (following the instructions in the codex), the admin works fine (and I can change to the theme that I want), but when I bring up the application, none of the rules in the stylesheet are being applied.

WordPress can find the theme files (e.g. the custom menu coded in header.php of the theme shows up), and the content looks pretty much okay, but nothing is styled.

In the HTML the path to the stylesheet looks right, e.g.

http://my-domain/the-new-directory/wp-content/themes/mytheme/style.css

I’m stumped.