Grunt concat no errors but doesn't works - gruntjs

Question

Hi Grunt concat doesn't shows errors, but it doesn't concentrate my styles.css file. Here is a screenshot of it:
link: http://i.imgur.com/gHlbROe.png
And here is a screenshot of my css file, which still isn't being concatenated(also you can see my folder structure here below):
link: http://i.imgur.com/UlGWQv1.png
And here is my gruntfile.js (Maybe I should have a different separator in concat_css.):
module.exports = function(grunt) {
grunt.initConfig({
less: {
development: {
options: {
compress: true,
yuicompress: true,
optimization: 2,
css: ['concat']
},
files: {
"css/styles.css": "css/styles.less" // destination file and source file
}
}
},
concat_css: {
options: {
// Task-specific options go here.
separator: '}'
},
all: {
src: ["css/styles.css"],
dest: "css/styles.css"
},
},
watch: {
styles: {
files: ['css/styles.less'], // which files to watch
tasks: ['less', 'concat_css'],
options: {
nospawn: true
}
}
}
});
grunt.loadNpmTasks('grunt-contrib-less');
grunt.loadNpmTasks('grunt-concat-css');
grunt.loadNpmTasks('grunt-contrib-watch');
grunt.registerTask('default', ['less', 'watch', 'concat_css']);
};

Answer 1

I'm pretty sure the task is called concat, not concat_css. You're config will need to match that name (that is, you should not be using concat_css at all). Aside from that, why would you make the separator the closing brace (})? If you ever have more than one file that will almost certainly cause a syntax error in the concatenated CSS file. I would leave out that option unless you have a specific need for it.
concat: { // <-- change this to match the name of the task: "concat"
all: {
src: ["css/styles.css"],
dest: "css/styles.css"
},
},