pdfkit does not load css and JavaScript
To generate URLs for static files, use the special 'static' endpoint name: http://flask.pocoo.org/docs/0.10/quickstart/#static-files
<link href="{{ url_for('static', filename='css/bootstrap.css') }}" rel="stylesheet" ><link href="{{ url_for('static', filename='css/bootstrap-theme.css') }}" rel="stylesheet">Update:Using _external=True may also fix the issue by providing an absolute url. eg:
<link href="{{ url_for('static', filename='css/bootstrap.css', _external=True) }}" rel="stylesheet" >
I was able to get this to work using pdfkit by including the full path in my jinja2 template:
<link rel="stylesheet" href="file:///Users/paul/code/pdfmaker/templates/css/styles.css">