It has an optional fluid grid: http://twitter.github.com/bootstrap/examples/fluid.html http://twitter.github.com/bootstrap/examples/fluid.html In any case, fi

It has an optional fluid grid: http://twitter.github.com/bootstrap/examples/fluid.html http://twitter.github.com/bootstrap/examples/fluid.html In any case, fixed width layouts which adapt to screen sizes are also considered a form of responsive design.