我应该在哪里引导我的网站？

I want my site to be fluid/responsive to whatever device the user has; I reckon more often than not it will be a cell "phone," but I am developing on a laptop, so there's a mismatch between what I see at design time and what most users will see. Of course, I can run emulators/simulators, etc. But my point is that I want the site to automatically adjust to the size/aspect ratio/orientation the device at any given moment. From what I've read, the easiest way to accomplish this is to leverage Twitter Bootstraps capabilities by referencing their CSS file and adding a few class declarations to various tags in my html. I'm wondering just where I need to add these.I want my site to be fluid/responsive to whatev