diff --git a/util/lesscss.py b/util/lesscss.py
index 18382bd..c422920 100644
--- a/util/lesscss.py
+++ b/util/lesscss.py
@@ -7,11 +7,18 @@ import sys
 filename = sys.argv[1]
 pqd = pq(filename=filename)
 raw_data = open(filename, 'rb').read()
+if raw_data.count('<pre'):
+    def keep(s):
+        return s == '.w' or s.startswith('.w ') or s == '.b' or s.startswith('.b ')
+else:
+    def keep(s):
+        return False
+
 original_css = raw_data.split('<style>', 1)[1].split('</style>', 1)[0]
 new_css = ''
 for rule in original_css.split('}')[:-1]:
     selectors, properties = rule.split('{', 1)
-    selectors = ','.join([s for s in selectors.split(',') if pqd(s.split(':', 1)[0])])
+    selectors = ','.join([s for s in selectors.split(',') if keep(s) or pqd(s.split(':', 1)[0])])
     if selectors:
         new_css += '%s{%s}' % (selectors, properties)
 open(filename, 'wb').write(raw_data.replace(original_css, new_css))