gulpfile.js

var gulp = require('gulp');
var sass = require('gulp-sass');
var autoprefixer = require('gulp-autoprefixer');
var sourcemaps = require('gulp-sourcemaps');
var plumber = require("gulp-plumber");
var notify = require("gulp-notify");
var browserSync = require('browser-sync').create();

gulp.task('default',['serve']);

// Static Server + watching scss/html files
gulp.task('serve', ['sass'], function() {
  browserSync.init({
    server: './'
  });

  gulp.watch('./scss/**/*.scss', ['sass']);
  gulp.watch('./*.html').on('change', browserSync.reload);
});

gulp.task('sass', function(){
    gulp.src('./scss/style.scss')
    .pipe(plumber({ errorHandler: notify.onError("Error: <%= error.message %>") }))
    .pipe(sourcemaps.init())
    .pipe(sass({outputStyle: 'compressed'}).on('error', sass.logError))
    .pipe(autoprefixer({
        browsers: ["last 2 versions"],
        cascade: false
    }))
    .pipe(sourcemaps.write('.'))
    .pipe(gulp.dest('./scss/'))
    .pipe(browserSync.stream());
});