May I use a css file with my template ?

[Dav1d]

Hello

When I do my template, I would like to write something like that : <td class="paintbeauty">, but the class paintbeauty, is in the file mystyles.css, well the point it's I don't know if do something like that it's possible, and if yes, I would like to know how .

Thanks in advance

Regards.