You should be able to find everything you need with any modern web browser's built in browser tools. There's really no need to look at the style.css file separately, and that's not even all the CSS anyway. I personally really like Chrome's web inspector, but the newest one built in to Firefox is also pretty nice. In Internet Explorer, you can go to Tools → Developer Tools to open a web inspector, but I think it's a little harder to navigate.
I know what you mean about wanting to scan the CSS. If you use something like Firefox's built in "Style Editor," you should be able to see the expanded, unminified version of the CSS.
You really don't need an extra link to look at the theme's stylesheet, and that isn't a comprehensive view of all the CSS that is being loaded anyway. Using browser tools is a better route—you should try them out!