This plugin can be used to load a CSS file.
Make sure the CSS file will only apply so specific items within your widget, so use very specific class names to target your widget.

A good practice is to mark your root domNode with a unique class (e.g. "bcMySpecificPlugin"), and target all CSS rules within this class.

<!-- mySpecificPlugin.html -->
<div class="bcMySpecificPlugin">
  <div class="myDivClass">
   Example text in red.
/* mySpecificPlugin.css */
.bcMySpecificPlugin .myDivClass {
  color: red;

Loading the above CSS file goes as follows:

/* mySpecificPlugin.js */
], function(){
  // widget here, the CSS file is automatically loaded.