If you are a savvy web developer and know your way around the front-end of a website, you might want to add your own CSS to overwrite some of the standard theme settings to achieve a more customized look and feel for your video site.
To enter the custom CSS for your site, hover your cursor over "Site" at the top of the page, select "Theme Design," and navigate to "Editor" on the lefthand side of the screen. There, you can enter CSS to your heart's content. You can review your edits in the Preview of your video site. When you are finished making changes, click "Publish Changes" in the upper righthand corner of the page.