rework css to better match gitiles

tools/md_browser/md_browser.py

 #!/usr/bin/env python
 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Simple Markdown browser for a Git checkout."""
 from __future__ import print_function
 
 import SimpleHTTPServer
 import SocketServer
@@ skipping 112 matching lines @@
 
     # strip off the repo and branch info, if present, for compatibility
     # with gitiles.
     if path.startswith('/chromium/src/+/master'):
       path = path[len('/chromium/src/+/master'):]
 
     full_path = os.path.realpath(os.path.join(self.server.top_level, path[1:]))
 
     if not full_path.startswith(self.server.top_level):
       self._DoUnknown()
-    elif path == '/doc.css':
-      self._DoCSS('doc.css')
+    elif path in ('/base.css', '/doc.css', '/prettify.css'):
+      self._DoCSS(path[1:])
     elif not os.path.exists(full_path):
       self._DoNotFound()
     elif path.lower().endswith('.md'):
       self._DoMD(path)
     elif os.path.exists(full_path + '/README.md'):
       self._DoMD(path + '/README.md')
     else:
       self._DoUnknown()
 
   def _DoMD(self, path):
@@ skipping 118 matching lines @@
       contents.text = 'Contents'
       contents.tail = '\n'
       toc_aux = ElementTree.SubElement(toc_node, 'div', {'class': 'toc-aux'})
       toc_aux.text = '\n'
       toc_aux.append(ul_with_the_desired_toc_entries)
       toc_aux.tail = '\n'
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))