CSS isn’t added to my page

I’ve just started using CF7S. I’ve chosen a Skin, Template, and modified the template. When I view the form in my page, it’s present and has the right style tags present, but it doesn’t format to the style.

<form action="/contact-test/#wpcf7-f327-p328-o1" method="post" class="wpcf7-form cf7skins cf7t-contact cf7s-caspar" novalidate="novalidate">

When I check the source of my page, there’s no definition of these classes in any CSS – I can find the “wpcf7-form” one, but there’s nothing for any of the cf7s ones. There’s no link to any cf7s stylesheet in the header where all the plugin CSS files are linked.