How to use multiple CSS files in Meteor
You can find Meteor behaviour in this link: https://guide.meteor.com/structure.html
Inspite of these rules are more relevant for .js code and .html template files: Meteor merge and minimize all .css in a single file as long as they are provided by you and not on a CDN so you will find a single <link rel=”stylesheet”> reference in your <head>.
Remember to put all frontend files inside client folder, to avoid unnecessary server loading and availability.
So you can choose your convenient folder structure for .css files, for example put them all in client/stylesheets or use other subfolders to better manage them.