BrowserSync does not show my own css styles, just from materialize. Help

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

gulp.task('styles', () => {
         gulp.src('sass/**/*.scss')
        .pipe(sass().on('error', sass.logError))
        .pipe(sass())
        .pipe(gulp.dest('./css/'))
        .pipe(browserSync.stream());
        
});

gulp.task('default', function () {
    gulp.watch('./sass/**/*.scss', ['styles']);
  });

// codigo compilar sass en tiempo real

//servidor 

gulp.task('serve', ['styles'], function(){

    browserSync.init(["./css/*.css", "js/*.js"],{

        server:'./'
    });

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


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