I was trying to add a dropdown for top menu bar in a SharePoint 2013 site. I opened the site in SPD 2013 and followed the instructions as mentioned in How to create drop-down menu in the SharePoint Foundation subsite via SharePoint Designer.
Home Page got completely messed up. Sub-sites looks perfect. only root site home page got messed up
Now it looks like below screen shot.
v4.master to default page which is the original copy. Still I see the same.