Have you tried changing the link_to to find what it is that is causing
the problem, removing the style, trying different controller and
actions for example? If you can get to a working situation then work
back to a failing one something may become clear, or at least less
muddy.
It just goes to show how clever rails is, you asked for a link to
account/index, it generated a link to / but your route says that /
should go to account/index. So that's all right then.