We're in the process of making some major site updates, with improved detail pages about the content you want to download and improved ways of signing in.
As a result, some pages may not display properly at times. This is because older pages can cache themselves. You can normally fix this by performing a deep refresh of the page (by pressing the Ctrl-F5 keys simultaneously), which will fix most issues immediately.
This is a temporary situation while the new pages settle on the server.