Autoprefixer throws an error in Sublime Text. What's wrong?

Question

Sass

Question to the guru who uses Gulp.
Actually, I set up gulp according to the WebDesignMaster (youtuber) lesson. Everything worked yesterday. True, in main.sass I had only one line

body 
  background: #f00

Today I started trying to fully prescribe for other tags - an error came out

With this code

body
  font-size: 18px
  min-width: 320px
  position: relative
  line-height: em(30px)

If I put ";" at the end then everything works... but it's not SASS anymore ((
What am I doing wrong?(
If necessary, here is the gulpfiles.js code

var gulp         = require('gulp'),
    sass         = require('gulp-sass'),
    browserSync  = require('browser-sync'),
    concat       = require('gulp-concat'),
    uglify       = require('gulp-uglifyjs'),
    cssnano      = require('gulp-cssnano'),
    rename       = require('gulp-rename'),
    del          = require('del'),
    imagemin     = require('gulp-imagemin'),
    pngquant     = require('imagemin-pngquant'),
    cache        = require('gulp-cache'),
    autoprefixer = require('gulp-autoprefixer');

    gulp.task('sass', function(){
    	return gulp.src('app/sass/**/*.sass')
    	.pipe(sass())
    	.pipe(autoprefixer(['last 15 versions', '> 1%', 'ie 8', 'ie 7'], { cascade: true }))
    	.pipe(gulp.dest('app/css'))
    	.pipe(browserSync.reload({stream: true}))
    });

    gulp.task('scripts', function() {
    	return gulp.src([
    		'app/libs/jquery/dist/jquery.min.js',    		
    		'app/libs/magnific-popup/dist/magnific-popup.min.js'
    		])
    	.pipe(concat('libs.min.js'))
    	.pipe(uglify())
    	.pipe(gulp.dest('app/js'));
    })

    gulp.task('css-libs', ['sass'], function() {
    	return gulp.src('app/css/libs.css')
    	.pipe(cssnano())
    	.pipe(rename({suffix: '.min'}))
    	.pipe(gulp.dest('app/css'));
    });

    gulp.task('browser-sync', function() {
    	browserSync({
    		server: {
    			baseDir: 'app'
    		},
    		notify: false
    	});
    });

gulp.task('clean', function() {
  return del.sync('dist');
});

gulp.task('cache', function() {
  return cache.clearAll();
});

gulp.task('img', function() {
  return gulp.img('app/img/**/*')
  .pipe(cache(imagemin({
    interlaced: true,
    progressive: true,
    svgoPlugin: [{removeViewBox: false}],
    une: [pngquant()]
  })))
  .pipe(gulp.dest('dist/img'));
});
gulp.task('watch', ['browser-sync', 'css-libs', 'scripts'], function() {
gulp.watch('app/sass/**/*.sass', ['sass']);
gulp.watch('app/*.html', browserSync.reload);
gulp.watch('app/js/**/*.js', browserSync.reload);
    });

    gulp.task('build', ['clean', 'sass', 'scripts'], function() {

    	var buildCss = gulp.src([
    		'app/css/main.css',
    		'app/css/libs.min.css'
    		])
    	.pipe(gulp.dest('dist/css'));

    	var buildFonts = gulp.src('app/fonts/**/*')
    	.pipe(gulp.dest('dist/fonts'));

    	var buildJs = gulp.src('app/js/**/*')
    	.pipe(gulp.dest('dist/js'));

    	var buildHTml = gulp.src('app/*.html')
    	.pipe(gulp.dest('dist'));

    });

Answer 1

Do this:

.pipe(sass({ style: 'expanded' }))
.pipe(autoprefixer('last 2 versions', 'ios 7', 'android 4'))

15 versions of IE are not needed :)