安裝兩個依賴gulp-autoprefixer和browserslist，然後改變package.json檔案和gulpfile檔案

package.json：

{
  "name": "01",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "server": "webpack-dev-server --content-base ./ --port 8080",
    "build": "gulp build && webpack"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "babel-core": "^6.24.1",
    "babel-loader": "^6.4.1",
    "babel-preset-es2015": "^6.24.1",
    "babel-preset-react": "^6.24.1",
    "browserslist": "^2.1.0",
    "css-loader": "^0.28.0",
    "gulp": "^3.9.1",
    "gulp-autoprefixer": "^3.1.1",
    "gulp-concat": "^2.6.1",
    "gulp-csso": "^3.0.0",
    "gulp-less": "^3.3.0",
    "less": "^2.7.2",
    "less-loader": "^4.0.3",
    "prop-types": "^15.5.8",
    "react": "^15.5.4",
    "react-dom": "^15.5.4",
    "style-loader": "^0.16.1",
    "webpack": "^2.4.1",
    "webpack-dev-server": "^2.4.4"
  }
  ,"browserslist": [
       "Chrome > 1",
       "Firefox > 1",
       "Opera  > 1",
       "ie >= 6",
       "Edge >= 9"
    ]
}
 

gulpfile檔案：

var path = require('path');
var gulp = require('gulp');
var less = require('gulp-less');
var csso = require('gulp-csso');
var concat = require('gulp-concat');
var fs = require("fs");
var autoprefixer = require('gulp-autoprefixer');
 
//https://www.npmjs.com/package/gulp-less
//定義了一個任務叫做less
gulp.task('less', function () {
  return gulp.src('./less/**/*.less')
    .pipe(less())
    .pipe(autoprefixer())
    .pipe(csso())
    .pipe(gulp.dest('./css'));
});


//定義了一個合併任務 
gulp.task('cssconcat', function() {
  return gulp.src('./css/**/*.css')
    .pipe(concat('all.css'))
    .pipe(gulp.dest('./dist/'));
});

//定義一個刪除資料夾的任務，NodeJS規定只能刪除空資料夾，這裡使用了遞迴來迴圈刪除
gulp.task("clean",function(){
    var deleteFolder = function(path) {
    	var files = [];
    	if( fs.existsSync(path) ) {
        	files = fs.readdirSync(path);
        	files.forEach(function(file,index){
            	var curPath = path + "/" + file;
            	if(fs.statSync(curPath).isDirectory()) { // recurse
                	deleteFolder(curPath);
            	} else { // delete file
               	 fs.unlinkSync(curPath);
           	 	}
       		 });
        	fs.rmdirSync(path);
    	}
	};

	deleteFolder("./css")
});

//工作流
gulp.task("dev",["less"]);
gulp.task("build",["less" , "cssconcat" , "clean"]);

//監聽
gulp.watch('./less/**/*.less' , ["dev"]);