Thread:Fredy-san/@comment-26131865-20160304164140/@comment-24659969-20160328142129

Well it is default table background color. If you want to overwrite it, simply write the background color

{| style="margin:0px auto;width:100%; background:RED; " class="wikitable mw-collapsible mw-collapsed" id="mw-customcollapsible-white" ....

Also, if you are using table already, div container is not needed.