Problems adding elements (e.g. paper-card) to the hugo Polymer theme

[Lithimlin]

Description

I am unable to add the components paper-card and paper-button to my website using bower together with the Hugo Polymer theme.

Expected outcome

After executing the command bower install --save PolmerElement/paper-card, the folder is added along with the contents and the necessary files are edited.
Then, when adding the element to the page (importing it with <link rel="import" href="{{$baseurl}}/bower_components/paper-card/paper-card.html"> and then using it), the element is shown on the website and can be interacted with.

Actual outcome

The element folders are added with their content but even after importing the element and trying to use it, nothing happens with it. No paper-card is shown.

Live Demo

Unfortunately, I do not have a live demo of my issue, as the website with this problem is not live yet. I do have a live version of the expected outcome though:
https://www.fs-ist.de
Additionally, here is a screenshot of the actual behavior:

Steps to reproduce

1. Download and install hugo
2. Install the Polymer theme
3. Attempt to add the elements paper-card and paper-button to the bower_components

Browsers Affected

This is a browser-independent issue.

• Chrome
• Firefox
• Safari 9
• Safari 8
• Safari 7
• Edge
• IE 11
• IE 10