npm and error messages

node_modules/csso/lib/compressor/compress/Atrule.js

@@ -0,0 +1,9 @@
+var resolveKeyword = require('../../utils/names.js').keyword;
+var compressKeyframes = require('./atrule/keyframes.js');
+
+module.exports = function(node) {
+    // compress @keyframe selectors
+    if (resolveKeyword(node.name).name === 'keyframes') {
+        compressKeyframes(node);
+    }
+};