Gulp / Myth

gulpfile.js

var gulp = require("gulp")
var gutil = require("gulp-util")
var plumber = require("gulp-plumber")
var myth = require("gulp-myth")
var csso = require("gulp-csso")
var watch = false

gulp.task("styles", function() {
  return gulp.src("./src/css/*.css")
    .pipe(watch ? plumber() : gutil.noop())
    .pipe(myth({sourcemap: !gulp.env.production}))
    .pipe(gulp.env.production ? csso() : gutil.noop())
    .pipe(gulp.dest("./dist/css/"))
})

gulp.task("dev", ["styles"], function() {
  watch = true
  gulp.watch("./src/css/**/*", ["styles"])
})