引导。当使用触控笔进行解析时，触控笔中断

I am trying to use stylus a css preprocessor with twitter bootstrap version 2.04. When I download boostrap I run "stylus --css < bootstrap.css > bootstrap.styl" so that I can create a bootstrap.styl file. However I get the following error when my browser tries to parse bootstrap.stylI am trying to use stylus a css preprocessor wi