If you have some Custom CSS that you need to apply for your SharePoint or Office365 site, you can easily do this using the Custom CSS feature in the Site Branding & Customization Tool by following these steps.


Step 1: Open the Site Customization Tool


Go to Site Settings


Then to ShortPoint Dashboard

Click on the Site Customizations tile


Then Click on the Customize my site button


Step 2: Apply your Custom CSS

Once the branding & customization tool is opened, Navigate into Utilities 



Then to Custom CSS



paste your CSS Customizations into the Custom CSS Field, and click Apply



And of course, do not forget to Publish your changes in order to make then available for your site visitors