Undo merge of #11778 and use cleancss min option

Gruntfile.js

@@ -117,6 +117,16 @@ module.exports = function (grunt) {
           'dist/css/<%= pkg.name %>-theme.css': 'less/theme.less'
         }
       },
+      minify: {
+        options: {
+          cleancss: true,
+          report: 'min'
+        },
+        files: {
+          'dist/css/<%= pkg.name %>.min.css': 'dist/css/<%= pkg.name %>.css',
+          'dist/css/<%= pkg.name %>-theme.min.css': 'dist/css/<%= pkg.name %>-theme.css'
+        }
+      }
     },
 
     usebanner: {
@@ -128,26 +138,14 @@ module.exports = function (grunt) {
         files: {
           src: [
             'dist/css/<%= pkg.name %>.css',
+            'dist/css/<%= pkg.name %>.min.css',
             'dist/css/<%= pkg.name %>-theme.css',
+            'dist/css/<%= pkg.name %>-theme.min.css',
           ]
         }
       }
     },
 
-    cssmin: {
-      compress: {
-        options: {
-          keepSpecialComments: 1,
-          report: 'min',
-          selectorsMergeMode: 'ie8'
-        },
-        files: {
-          'dist/css/<%= pkg.name %>.min.css': 'dist/css/<%= pkg.name %>.css',
-          'dist/css/<%= pkg.name %>-theme.min.css': 'dist/css/<%= pkg.name %>-theme.css'
-        }
-      }
-    },
-
     csscomb: {
       sort: {
         options: {
@@ -330,7 +328,6 @@ module.exports = function (grunt) {
   grunt.loadNpmTasks('grunt-contrib-connect');
   grunt.loadNpmTasks('grunt-contrib-copy');
   grunt.loadNpmTasks('grunt-contrib-csslint');
-  grunt.loadNpmTasks('grunt-contrib-cssmin');
   grunt.loadNpmTasks('grunt-contrib-jshint');
   grunt.loadNpmTasks('grunt-contrib-less');
   grunt.loadNpmTasks('grunt-contrib-qunit');
@@ -359,7 +356,7 @@ module.exports = function (grunt) {
   grunt.registerTask('dist-js', ['concat', 'uglify']);
 
   // CSS distribution task.
-  grunt.registerTask('dist-css', ['less', 'cssmin', 'csscomb', 'usebanner']);
+  grunt.registerTask('dist-css', ['less', 'csscomb', 'usebanner']);
 
   // Fonts distribution task.
   grunt.registerTask('dist-fonts', ['copy']);

package.json

@@ -28,7 +28,6 @@
     , "grunt-contrib-connect": "~0.5.0"
     , "grunt-contrib-copy": "~0.4.1"
     , "grunt-contrib-csslint": "~0.2.0"
-    , "grunt-contrib-cssmin": "~0.7.0"
     , "grunt-contrib-jshint": "~0.7.0"
     , "grunt-contrib-less": "~0.8.0"
     , "grunt-contrib-qunit": "~0.3.0"