A friend of mine who has got a live Wordpress website has bought a new theme. Before he's going to install and use it, he would like to adapt the theme's styles to his current web design. I uploaded the theme files on a different server because I hoped that I can preview the pages while I work on the CSS, but that doesn't work (blank pages).
Is there any possibility to work on the theme CSS files incl. page preview without already installing the new theme?