var gulp = require('gulp'),
concatCSS = require('gulp-concat-css'),
rename = require('gulp-rename'),
prefix = require('gulp-autoprefixer'),
minifyCSS = require('gulp-minify-css');
gulp.task('default', function() {
gulp.src('stylus/*.css')
.pipe(minifyCSS())
.pipe(prefix('last 3 versions', '>5%', 'ie9'))
.pipe(concatCSS("bundle.css"))
.pipe(rename('bundle.min.css'))
.pipe(gulp.dest('app/css/'));
});
gulp.task('watch', function() {
gulp.watch('stylus/*.css', ['default'])
})
API
autoprefixer([options])