The preferred way to style components in the GlueStick environment is to use Radium, but we also actively use and support CSS and SASS.
If you want to include a base stylesheet (like bootstrap css), you can import your stylesheet at the top of any file and it will be included when the page loads. Any updates to your styles will also be hot loaded. You can use plain CSS or SASS.
Example: Edit /Index.js
import React, { Component } from "react";
import "assets/css/my-custom-css.css";
…
The code above will automatically extract the css from the referenced file and include it in a base css file that is included on new page loads. References to images and font files will automatically be handled as well.
Please note that if you use external modules (packages in node_modules), you need
to use the relative path or compiled alias. Otherwise, those modules won't be
compiled - loaders won't process them.
Read more here
import "compiled/bootstrap/dist/css/bootstrap.css";
If you would like to see better CSS support, please submit a pull request :)