1) The entire content is collapsed under a single heading on the page "MediaWiki is a collaboration and documentation platform brought to you by a vibrant community.".
Solution: wrap the whole content in a DIV this will disable section collapsing on mobile and make the page more usable.
2) The talk button is inaccessible
The title is hacked with opacity:0;position:absolute; which impacts the talk tab. There should be no need to do this - the template is used on the main page not here.
Please remove this code:
{{DISPLAYTITLE:<span style="opacity:0;position:absolute;">{{FULLPAGENAME}}</span>}}