old_contents: var gulp = require('gulp');
  var sourcemaps = require('gulp-sourcemaps');
  var stylus = require('gulp-stylus');
  var rename = require('gulp-rename');
  var cssnano = require('gulp-cssnano');
  var poststylus = require('poststylus');
  var stylint = require('gulp-stylint');
  
  var mainStyl = './styl/main.styl';
  
  gulp.task('build:dev', function() {
      gulp.src(mainStyl)
          .pipe(sourcemaps.init())
          .pipe(stylus({ use: poststylus([ 'autoprefixer' ]) }))
          .pipe(sourcemaps.write())
          .pipe(rename('baremetal.css'))
          .pipe(gulp.dest('./build/development'));
  });
  
  gulp.task('build:prod', function() {
      gulp.src(mainStyl)
          .pipe(stylus())
          .pipe(cssnano({ discardComments: false }))
          .pipe(rename('baremetal.min.css'))
          .pipe(gulp.dest('./build/production'));
      gulp.src(mainStyl)
          .pipe(stylus({ use: poststylus([ 'autoprefixer' ]) }))
          .pipe(rename('baremetal.css'))
          .pipe(gulp.dest('./build/production'));
  });
  
  gulp.task('lint', function() {
      return gulp.src('./styl/**/*.styl')
          .pipe(stylint())
          .pipe(stylint.reporter());
  });
  
  gulp.task('stylus:watch', function() {
      gulp.watch('./styl/**/*.styl', ['lint', 'build:dev']);
  });
  
  gulp.task('watch', ['build:dev', 'stylus:watch']);
  
  gulp.task('default', ['lint', 'build:dev', 'build:prod']);
  
new_contents: var gulp = require('gulp');
  var sourcemaps = require('gulp-sourcemaps');
  var stylus = require('gulp-stylus');
  var rename = require('gulp-rename');
  var cssnano = require('gulp-cssnano');
  var poststylus = require('poststylus');
  var stylint = require('gulp-stylint');
  
  var mainStyl = './styl/main.styl';
  
  gulp.task('build:dev', function() {
      gulp.src(mainStyl)
          .pipe(sourcemaps.init())
          .pipe(stylus({ use: poststylus([ 'autoprefixer' ]) }))
          .pipe(sourcemaps.write())
          .pipe(rename('baremetal.css'))
          .pipe(gulp.dest('./build/development'));
  });
  
  gulp.task('build:prod', function() {
      gulp.src(mainStyl)
          .pipe(stylus({ use: poststylus([ 'autoprefixer' ]) }))
          .pipe(cssnano({ discardComments: false }))
          .pipe(rename('baremetal.min.css'))
          .pipe(gulp.dest('./build/production'));
      gulp.src(mainStyl)
          .pipe(stylus({ use: poststylus([ 'autoprefixer' ]) }))
          .pipe(rename('baremetal.css'))
          .pipe(gulp.dest('./build/production'));
  });
  
  gulp.task('lint', function() {
      return gulp.src('./styl/**/*.styl')
          .pipe(stylint())
          .pipe(stylint.reporter());
  });
  
  gulp.task('stylus:watch', function() {
      gulp.watch('./styl/**/*.styl', ['lint', 'build:dev']);
  });
  
  gulp.task('watch', ['build:dev', 'stylus:watch']);
  
  gulp.task('default', ['lint', 'build:dev', 'build:prod']);
  
subject: Fix missing prefixes on minified production build