added (c) comment to main CSS files

src/prettify.css

@@ -1,5 +1,23 @@
+/**
+ * @license
+ * Copyright (C) 2015 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 /* Pretty printing styles. Used with prettify.js. */
 
+
 /* SPAN elements with the classes below are added by prettyprint. */
 .pln { color: #000 }  /* plain text */
 

tests/test_styles.css

@@ -1,3 +1,20 @@
+/**
+ * @license
+ * Copyright (C) 2015 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
 /* Used by error reporting code in test_base.js */
 .mismatch { background: #fee; font-weight: bold }
 span.annot { margin:2px 2px 2px 3em; border:1px dotted #88f; background:#eef;