Here is an example using bootstrap on a single page, the scripts and styles decoration shall be the same.
Bootstrap Menu[
^]
I see your code has registered style and script bundle in bundleconfig.cs but did the layout page render it? Also, verify your styles and scripts location, make sure the files are in the correct location.
@Styles.Render("~/css")
@Scripts.Render("~/js")
I think this reference is wrong, should it be ~/Content/bootstrap.css?
<link href="~/css/bootstrap.css" rel="stylesheet" />