@media (min-width: 320px) and (max-width:359px){// 对于320-359 按照320px来计算/* 720/320 = 2.25*/ html{font-size: 27.78%}  // 62.5% / 2.25
}
@media (min-width: 360px) and (max-width:399px){// 对于360-399按照360px来计算/* 720/360 = 2*/ html{font-size: 31.25 %}  // 62.5% / 2
}
@media (min-width: 400px) and (max-width:450px){// 对于400-450按照400px来计算/* 720/400 = 1.8*/ html{font-size: 34.72 %}  // 62.5% / 1.8
}
@media (min-width: 640px) and (max-width:999px){// 对于640-999按照640px来计算/* 720/640 = 1.125 */ html{font-size: 55.56%}  // 62.5% / 1.125
}

@media (min-width: 320px) and (max-width:359px){/* 720/320 = 2.25*/margin-top = 40px / 2.25
}@media (min-width: 360px) and (max-width:399px){/* 720/360 = 2*/ margin-top = 40px / 2
}
@media (min-width: 400px) and (max-width:450px){/* 720/400 = 1.8*/ margin-top = 40px / 1.8
}
@media (min-width:640px) and (max-width:999px){/* 720/640 = 1.125 */ margin-top = 40px / 1.125
}

@media (min-width: 320px) and (max-width:359px){/* 720/320 = 2.25*/@multiple: 2.25;// 下面是所有的代码.xx {width:40px / @multiple; margin: 40px / @multiple;padding: 40px / @multiple; }
}
@media (min-width: 360px) and (max-width:399px){/* 720/360 = 2*/ @multiple: 2;// 下面是所有的代码.xx {width:40px / @multiple; margin: 40px / @multiple;padding: 40px / @multiple; }
}
@media (min-width: 400px) and (max-width:450px){/* 720/400 = 1.8*/ @multiple: 1.8;// 下面是所有的代码.xx {width:40px / @multiple; margin: 40px / @multiple;padding: 40px / @multiple; }
}
@media (min-width:640px) and (max-width:999px){/* 720/640 = 1.125 */ @multiple: 1.125;// 下面是所有的代码.xx {width:40px / @multiple; margin: 40px / @multiple;padding: 40px / @multiple; }
}

@media (min-width: 320px) and (max-width:359px){/* 720/320 = 2.25*/@multiple: 2.25;.mixin();// 下面可以写自己私有的css
 }
@media (min-width:360px) and (max-width: 399px) {/* 720/360 = 2*/@multiple: 2;.mixin();// 下面可以写自己私有的css
 }@media (min-width: 400px) and (max-width:450px){/* 720/400 = 1.8*/@multiple: 1.8;.mixin();// 下面可以写自己私有的css
 }@media (min-width: 640px) and (max-width:999px){/* 720/640 = 1.125*/@multiple: 1.125;.mixin();// 下面可以写自己私有的css}

{"name": "app2","version": "1.0.0","description": "this is for study gulp project","main": "index.js","dependencies": {"gulp-less": "^3.0.3","gulp": "^3.9.0"},"devDependencies": {},"scripts": {"test": "test"},"repository": {"type": "git","url": "http://www.github.com/xx"},"keywords": ["gulp-less"],"author": "tugenhua","license": "ISC"
}

{"name": "app2","version": "1.0.0","description": "this is for study gulp project","main": "index.js","dependencies": {"gulp-less": "^3.0.3","gulp": "^3.9.0"},"devDependencies": {"gulp-less": "^3.0.3"},"scripts": {"test": "test"},"repository": {"type": "git","url": "http://www.github.com/xx"},"keywords": ["gulp-less"],"author": "tugenhua","license": "ISC"
}

//导入工具包 require('node_modules里对应模块')
var gulp = require('gulp'), //本地安装gulp所用到的地方
less = require('gulp-less');
//定义一个testLess任务（自定义任务名称）
gulp.task('testLess', function () {gulp.src('./css/index.less') //该任务针对的文件.pipe(less()) //该任务调用的模块.pipe(gulp.dest('./css')); //将会在src/css下生成index.css
});
gulp.task('testWatch', function () {gulp.watch('./css/*.less', ['testLess']); //当所有less文件发生改变时，调用testLess任务
});
//gulp.task('default',['testLess']); //定义默认任务
//gulp.task(name[, deps], fn) 定义任务  name：任务名称 deps：依赖任务名称 fn：回调函数
//gulp.src(globs[, options]) 执行任务处理的文件  globs：处理的文件路径(字符串或者字符串数组)
//gulp.dest(path[, options]) 处理完后文件生成路径