Always display the footer at the bottom of the browser window

When a page is small enough (both the content and the left menu are not high), the XWiki footer appears to "float" in the middle of the page.

A few CSS rules achieve the desired outcome:

The CSS rules in question:

html, body, #xwikimaincontainer

{   height: 100%; }

#xwikimaincontainerinner, #edit

{   height: 100%;   display: flex;   flex-direction: column; }

#contentcontainer

{   flex: 1; }