npm install --save-dev mat-mcssvarmat=require('mat')varmcss=require('mat-mcss')varautoprefixer=require('mat-autoprefixer')mat.task('mcss',function(){mat.url([/.*\.css/]).rewrite([[/\.css/g,'.mcss']]).use(mcss()).use(autoprefixer({browsers: ['last 2 versions'],cascade: false}))})See the Mcss options.