Gulp не компилит sass в css

Здравствуйте, коллеги!

Пришлось поработать с чужим шаблоном, столкнулся с проблемой sass в css не собирается, хотя jade в html делает это без проблем.Куда посмотреть, подскажите.

Спасибо.

gulpfile.js:

'use strict';
      const gulp = require('gulp');
      const sass = require('gulp-sass');
      const debug = require('gulp-debug');
      const sourcemaps = require('gulp-sourcemaps');
      const autoprefixer = require('gulp-autoprefixer');
      const jade = require('gulp-jade');
      const plumber = require('gulp-plumber');
      const bs = require('browser-sync').create();
      const csscomb = require('gulp-csscomb');
      const babel = require('gulp-babel');
      const imagemin = require('gulp-imagemin');
      const spritesmith = require("gulp-spritesmith");
      const gulpif = require("gulp-if");
      gulp.task('serve', function () {
        bs.init({
          server: {
            baseDir: './'
          },
          notify: false
        });
        });
      gulp.task('sass', function (callback) {
        return gulp.src('../css/sass/*.sass')
          .pipe(sourcemaps.init())
          .pipe(sass().on('error', sass.logError))
          .pipe(debug({title: 'sass:'}))
          .pipe(autoprefixer({
            browsers: [
              'Chrome >= 35',
              'Firefox >= 31',
              'Edge >= 12',
              'Explorer >= 9',
              'iOS >= 8',
              'Safari >= 8',
              'Android 2.3',
              'Android >= 4',
              'Opera >= 12'
            ],
            cascade: true
          }))
          .pipe(debug({title: 'prefx:'}))
          .pipe(sourcemaps.write('.', {
            includeContent: false,
            sourceRoot: 'source'
          }))
          .pipe(debug({title: 'maps:'}))
          .pipe(csscomb())
          .pipe(gulp.dest('../css'));
        callback();
      });
      gulp.task('templates', function (callback) {
        gulp.src('jade/*.jade')
          .pipe(plumber())
          .pipe(jade({
            pretty: true
          }))
          .pipe(gulp.dest('.'))
          .pipe(debug({title: 'jade:'}));
        callback();
      });
      gulp.task('imagemin', () =>
        gulp.src('../images/nonoptimised/*')
          .pipe(imagemin())
          .pipe(gulp.dest('images'))
      );
      gulp.task('sprites', () =>
        gulp.src('../images/sprite/*.png')
          .pipe(spritesmith({
            imgName: 'sprite.png',
            styleName: 'sprite.css',
            imgPath: '../images/sprite.png'
          }))
          .pipe(gulpif('*.png', gulp.dest('../images/nonoptimised/')))
          .pipe(gulpif('*.css', gulp.dest('../css/')))
      );
      gulp.task('watch', ['sass', 'serve'], function() {
        gulp.watch('css/sass/**/*.*', ['sass']);
        gulp.watch('jade/**/*.*', ['templates']);
        gulp.watch('images/nonoptimised/*.*', ['imagemin']);
        gulp.watch('images/sprite/*.*', ['sprites']);
        gulp.watch("css/*.css").on('change', bs.reload);
        gulp.watch("*.html").on('change', bs.reload);
      });
      gulp.task('default', ['serve', 'templates', 'sass', 'sprites', 'imagemin', 'watch']);