How to make friends with Webpack and PostCSS correctly, namely with postcss-move-media?

Question

webpack

I connected PostCSS to the webpack with the postcss-move-media plugin.
If the media queries are in one css file, then it merges them correctly, and if in different modules, then it does nothing.
It is possible, as I understand webpack, that postcss-move-media fires on each module, but not the resulting css file.
How can this be overcome?
A series of loaders for css:

style-loader!css-loader!postcss-loader!stylus-loader