cmd

1. copy above files to your local folder
2. run `npm install`
3. run `npm -g gulp`
4. run `gulp sass`
5. run `gulp browser-sync`

gulpfile.js

var gulp = require('gulp');
var sass = require('gulp-sass');
var concat = require('gulp-concat');
var browserSync = require('browser-sync').create();

var config = {
  sassFolder: 'scss/*.scss',
  compiledCssFile: 'app.css',
  cssFolder: 'css/'
}

gulp.task('sass', function() {
  return gulp.src(config.sassFolder)
    .pipe(sass().on('error', function(err) {
      console.log(err.toString());
      this.emit('end');
    }))
    .pipe(concat(config.compiledCssFile))
    .pipe(gulp.dest(config.cssFolder));
});

gulp.task('browser-sync', function() {
  browserSync.init({
    server: {
      baseDir: './'
    }
  });
});

package.json

{
  "name": "demo",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "browser-sync": "^2.16.0",
    "gulp": "^3.9.1",
    "gulp-concat": "^2.6.0",
    "gulp-sass": "^2.3.2"
  }
}