Fix CSS minification

gulpfile.js

@@ -24,8 +24,8 @@ gulp.task('css', function(){
     ]))
     .pipe(sourcemaps.init())
     .pipe(autoprefixer('last 2 version', 'ios 6', 'android 4'))
-    .pipe(minifyCSS())
     .pipe(concat('hues-min.css'))
+    .pipe(minifyCSS())
     .pipe(sourcemaps.write("."))
     .pipe(gulp.dest('css'));
 });