when render a .jade, node.js cannot find the static files

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It's ok that I can get files in directory public when get "localhost:3000/movies", but if I add '/' to the end of url, that is "localhost:3000/movies/",something goes wrong, the css file in public cannot be get. how to solve this problem if I want to visit "localhost:3000/movies/moive" with css style?

via loick