How to use the CSS classes auto completion on WebStorm for CSS files imported from CDN like this?
<link rel="stylesheet" href="https://netdna.bootstrapcdn.com/bootstrap/3.0.0-rc1/css/bootstrap.min.css">
Only files located under your project root are used for completion/navigation/error highlighting, WebStorm doesn't use online resourses for types resolving. So you have to download the css and reference it using the relative URL to make the completion work