Build style with sourcemap for testing

gulpfile.js

gulp.task('styles', function() {
    return gulp.src('./src/scss/main.scss')
        .pipe(sourcemaps.init())
        .pipe(sass.sync({outputStyle: 'compressed'}).on('error', sass.logError))
        .pipe(rename({ extname: '.min.css' }))
        .pipe(livereload())
        .pipe(sourcemaps.write('.'))
        .pipe(gulp.dest('./assets/css/'));
});