diff --git a/styles/h5p.css b/styles/h5p.css
index d95af3e..8d8e9a0 100644
--- a/styles/h5p.css
+++ b/styles/h5p.css
@@ -49,6 +49,11 @@ html.h5p-iframe .h5p-semi-fullscreen .h5p-content {
   position: relative;
   z-index: 1;
 }
+body.h5p-semi-fullscreen {
+  position: fixed;
+  width: 100%;
+  height: 100%;
+}
 .h5p-container.h5p-semi-fullscreen {
   position: fixed;
   top: 0;