How to add CSS to blueprint?

Hi, I want to add CSS styles to my blueprint plugin. I’ve already added the css file into the atlassian-plugin.xml file as such

<resource type="download" name="comparator-plugin.css" location="/css/comparator-plugin.css"/>

but the page generated does not have any of the styles in the css file.
How do go about doing so? Thank you

I have the same question.