Execution of copy has no effect?

[ghost]

I've tried to copy a .css file bower_components/components-font-awesome/css/font-awesome.min.css into a target directory like this:

module.exports = function(grunt) {

  // Project configuration.
  grunt.initConfig({
    pkg: grunt.file.readJSON('package.json'),
    uglify: {
      options: {
        banner: '/*! <%= pkg.name %> <%= grunt.template.today("yyyy-mm-dd") %> */\n'
      },
      build: {
        src: 'src/main/webapp/js/**/*/<%= pkg.name %>.js',
        dest: 'build/<%= pkg.name %>.min.js'
      }
    },
    
    copy: {
		main: {
			//files: {
				expand: true,
			    cwd: '/',
				src: 'bower_components/components-font-awesome/css/font-awesome.min.css', 
				dest: 'src/main/webapp/css/' 
			//}
	 
		}
	}
    
  });
  
  grunt.loadNpmTasks('grunt-contrib-uglify');
  grunt.loadNpmTasks('grunt-contrib-copy');


  // Default task(s).
  grunt.registerTask('default', ['copy']);

};

but I am not getting anything copied. grunt -v gives me just

Initializing
Command-line options: --verbose

Reading "Gruntfile.js" Gruntfile...OK

Registering Gruntfile tasks.
Reading package.json...OK
Parsing package.json...OK
Initializing config...OK

Registering "grunt-contrib-uglify" local Npm module tasks.
Reading /media/Data/workspaces/git/easy-model-access/ema-server/web/node_modules/grunt-contrib-uglify/package.json...OK
Parsing /media/Data/workspaces/git/easy-model-access/ema-server/web/node_modules/grunt-contrib-uglify/package.json...OK
Loading "uglify.js" tasks...OK
+ uglify

Registering "grunt-contrib-copy" local Npm module tasks.
Reading /media/Data/workspaces/git/easy-model-access/ema-server/web/node_modules/grunt-contrib-copy/package.json...OK
Parsing /media/Data/workspaces/git/easy-model-access/ema-server/web/node_modules/grunt-contrib-copy/package.json...OK
Loading "copy.js" tasks...OK
+ copy
Loading "Gruntfile.js" tasks...OK
+ default

No tasks specified, running default tasks.
Running tasks: default

Running "default" task

Running "copy" task

Running "copy:main" (copy) task
Verifying property copy.main exists in config...OK
Options: encoding="utf8", processContent=false, processContentExclude=[], timestamp=false, mode=false


Done.

What I need is to copy a few specific .css files from the bower_components into the distribution css directory. Any idea why this is not working?