ReplaceCSS is a web tool that allows you to extract inline styles out of your HTML and output them into a CSS Stylesheet.
The tool is hosted at replacecss.com. Just copy and paste your HTML into the site and click extract. There are some options on the site to use ID's over Classes just choose whatever suits best for you.
The site should be responsive on all devices. If you find any issues feel free to log them here on the issues tab.