Compiled css file not showing up?

Question

Sass

Good afternoon!
Having installed Gulp, I ran into a problem that it does not compile the sass file to css.
Project structure and code:
gulpfile.js

// подключение gulp к проекту
var gulp = require('gulp'),
    sass = require('gulp-sass');// подключаем gulp-sass

// создание тасков(инструкций)
gulp.task('sass', function () {
    return gulp.src('app/main.sass')
        .pipe(sass())
        .pipe(gulp.dest('app/css'))
});

Console (seemingly no errors):

Project structure:

The problem is that after the gulp sass command, the compiled css file does not appear in app/css.
Tell me what's the problem.
Thank you.

Answer 1

Compiles.
When will you all learn to formulate the question correctly? Just because the rules require a question heading does not mean that a question mark should simply be placed at the end.
On the topic
instead
of Your main.sass is not at the root of the app.
And what does gulpfile.js do inside the app? Its place is a directory above, next to node_modules.