CSS Input

Hi,

Does anyone know if there is any tool (probably a Chrome extention), that will allow you to inject a css sheet (stored on your server), into another site, for viewing purposes only.

I update / redesign a lot of different sites for my clients. I usually start by opening their site in Chrome and using the inspector to change a few things around in front of the client... however as soon as i close the tab, the changes are lost... so i'd like to be able to save the CSS code to a input-style.css file and save it to my server and then 'inject' it into my client's site for demonstration purposes.

Thanks in advance for your help.