Gulp does not output the finished files
gulp.task('styles', ['images'], function (){
var postCssOpts = [
assets({loadPaths: ['images/']}),
autoprefixer({browsers: ['last 2 versions', '>2%']}),
cssnano()
];
return gulp.src([
'/src/sass/materialize.scss',
'./src/style.sccs'
...