Merge pull request #22557 from overleaf/td-bs5-pdf-detach-height

Copy some <html> and <body> rules from BS3 to fix the detached PDF page

GitOrigin-RevId: 9c14bd4988811b857c8c3516e50589514b400ac1

services/web/frontend/stylesheets/bootstrap-5/base/layout.scss

@@ -1,5 +1,17 @@
+html {
+  height: 100%;
+}
+
+// Prevent potential for layout shifts on a page with fixed 100% height. This
+// can happen, for example, with the Grammarly extension in Firefox.
+html.fixed-size-document {
+  position: fixed;
+  width: 100%;
+}
+
 body {
   position: relative;
+  min-height: 100%;
 }
 
 .content {