自动加载css与Browersync

当我更改我的main.scss文件时，我似乎无法实现自动重新加载Browersync。我已经得到了Browsersync重新加载浏览器自动在html的变化，但不是css

使用gulp作为任务管理器。我在这里错过了什么让浏览器重新加载css更改后?或者在css更改后，是否Browersync和gulp集成不支持重新加载?

我在谷歌上搜索了一下这个话题，我注意到还有一些人也收到了同样的问题。

如果我弄不清楚，你会建议我用什么来自动加载css的变化?Chromedev工具吗?Nodemon吗?还是Chrome扩展?

这是我的gulpfile

// refferance gulp
var gulp = require('gulp');
// browser-sync
var browserSync = require('browser-sync');
var reload = browserSync.reload;
// other packages installed
var concat = require('gulp-concat');
var cssmin = require('gulp-minify-css');
var rename = require('gulp-rename');
var scss = require('gulp-sass');
var uglify = require('gulp-uglify');
var source = {
    scss: './/src/scss/*.scss',
    css: './/dest/css/*.css',
    html: './*.html'
};
// browser-sync task
gulp.task('browser-sync',['styles'], function(){
    browserSync({
        server:'./'
    });
    gulp.watch(source.scss,['scss']);
    gulp.watch(source.html).on('change',reload);
});
// scripts task
gulp.task('scripts', function(){
    // fetch all files in the .js extension in the /src/js directory
    return gulp.src('./src/js/*.js')
    // concatinate files and save as app.js
    .pipe(concat('app.js'))
    // save app.js in dest directory
    .pipe(gulp.dest('./dest/js/'))
    .pipe(uglify())
    // minfiy file and rename to app.min.js
    .pipe(rename({
        suffix: '.min'
    }))
    // save in dest directory
    .pipe(gulp.dest('./dest/js'));
});

// styles task
gulp.task('styles', function(){
     // fetch all files with scss extension in /src/scss directory
    return gulp.src('./src/scss/*.scss')
    // compile scss
    .pipe(scss())
    // output css in css dest directory
    .pipe(gulp.dest('./dest/css/'))
    // minify css
    .pipe(cssmin())
    // rename as styles.min.css
    .pipe(rename({
        suffix: '.min'
    }))
    // save in same directory
    .pipe(gulp.dest('./dest/css'))
    // injecting css into browser via browsersync
    .pipe(reload({stream:true}));
});
// we use the watch task in the default task bellow
gulp.task('watch',function(){
    // watch js
    gulp.watch('./src/js/*.js',['scripts']);
    // watch scss
    gulp.watch('./src/scss/*.scss',['styles']);
});
// default task allows us to run all tasks at once by just runing `gulp` in command line
gulp.task('default', ['scripts', 'styles', 'browser-sync', 'watch']);