diff --git a/lib/filter.js b/lib/filter.js
index 8093f52..1456a22 100644
--- a/lib/filter.js
+++ b/lib/filter.js
@@ -51,7 +51,7 @@ function logic_css(str, data) {
     }
 
     return new Promise(function (resolve, reject) {
-        new CleanCSS(options).minify(str, function (err, result) {
+        new CleanCSS({level:2}).minify(str, function (err, result) {
             if (err) return reject(err);
             var saved = ((str.length - result.styles.length) / str.length * 100).toFixed(2);
             resolve(result.styles);
diff --git a/package-lock.json b/package-lock.json
index 15f292c..879d22f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "hexo-yam",
-  "version": "0.6.0",
+  "version": "0.6.1",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index f630fab..d725f08 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "hexo-yam",
   "description": "Yet Another Minifier. Minify and compress html, js and css",
-  "version": "0.6.0",
+  "version": "0.6.1",
   "readme": "README.md",
   "main": "index.js",
   "directories": {