diff --git a/src/themes/basic/_coverpage.styl b/src/themes/basic/_coverpage.styl
index 001493225..3ad8149ea 100644
--- a/src/themes/basic/_coverpage.styl
+++ b/src/themes/basic/_coverpage.styl
@@ -4,6 +4,7 @@ section.cover
   background-repeat no-repeat
   background-size cover
   height 100vh
+  width 100vw
   display none
 
   &.show