diff --git a/theme/standard/style/mod_assignment.css b/theme/standard/style/mod_assignment.css
index 05a16f39377..8f9b0209dc9 100644
--- a/theme/standard/style/mod_assignment.css
+++ b/theme/standard/style/mod_assignment.css
@@ -1,11 +1,11 @@
-.userpicture,
-.picture user,
-.picture teacher {
+.mod-assignment .userpicture,
+.mod-assignment .picture user,
+.mod-assignment .picture teacher {
   width:35px;
   height: 35px;
   vertical-align:top;
 }
-.modform {
+.mod-assignment .modform {
   text-align:center;
 }
 #wordcount {