Gruntfile.js

module.exports = function (grunt) {

    grunt.initConfig({

        myth: {
            dist: {
                files: {
                    'css/style.css': 'css/sources/style.css',
                    'css/themes/default.css': 'css/sources/themes/default.css',
                    'css/themes/xmas.css': 'css/sources/themes/xmas.css',
                    'css/themes/black.css': 'css/sources/themes/black.css',
                    'css/themes/stratis.css': 'css/sources/themes/stratis.css',
                }
            }
        },

        cmq: {
            dist: {
                files: {
                    'css/style.css': 'css/style.css',
                    'css/themes/default.css': 'css/themes/default.css',
                    'css/themes/xmas.css': 'css/themes/xmas.css',
                    'css/themes/black.css': 'css/themes/black.css',
                    'css/themes/stratis.css': 'css/themes/stratis.css',
                }
            },
        },

        //et on minify le css
        cssmin: {
            dist: {
                files: {'css/style.min.css': 'css/style.css',}
            },
            theme: {
                files: {'css/themes/default.min.css': 'css/themes/default.css'}
            },
            xmas: {
                files: {'css/themes/xmas.min.css': 'css/themes/xmas.css'}
            },
            black: {
                files: {'css/themes/black.min.css': 'css/themes/black.css'}
            },
            stratis: {
                files: {'css/themes/stratis.min.css': 'css/themes/stratis.css'}
            },

        },

        watch: {
            scripts: {
                files: ['css/**/*.css', 'css/*.css'],
                tasks: ['myth', 'cmq', 'cssmin'],
                options: {
                    spawn: false,
                },
            },
        },

    })

    grunt.loadNpmTasks('grunt-myth');
    grunt.loadNpmTasks('grunt-combine-media-queries');
    grunt.loadNpmTasks('grunt-css');
    grunt.loadNpmTasks('grunt-contrib-watch');

    grunt.registerTask('default', ['myth', 'cmq', 'cssmin'])
}