Update 'full screen' css for stud.ip 5.4

views/excalidraw/excalidraw_app.php

 <? if ($fullscreen) : ?>
     <!--  Hide all of Stud.IP's layout elements and remove extraneous padding.-->
     <style>
-        #barBottomContainer, #flex-header, .secondary-navigation, #layout-sidebar, #layout_footer, #page_title_container {
+        #barBottomContainer, #flex-header, .secondary-navigation, #layout-sidebar, #layout_footer, #page_title_container, #skip_link_navigation, #main-header, #sidebar, #main-footer, #scroll-to-top {
             display: none !important;
         }
 
         #layout_wrapper, #layout_content, #layout_container {
-            padding: 0;
+            padding: 0 !important;
+        }
+        body {
+            /* Prevent responsive css from switching this when the mobile breakpoint is reached */
+            display: grid !important;
+        }
+        #content-wrapper {
+            padding: 0 !important;
+            margin: 0 !important;
+            grid-column: 1/3 !important;
+            grid-row: 1/3 !important;
         }
     </style>
 <? endif ?>