Mobile Usability issues (from Google Search Console)

Google Search Console pointed out that

New issues detected on http://merlin-platform.eu/ and https://merlin-platform.eu/

To owner of http://merlin-platform.eu/ and https://merlin-platform.eu/,

Search Console has identified that your site is affected by 3 new issues of type Mobile Usability.

Top Issues (5 maximum)

The following issues were found on your site:

Viewport not set
Text too small to read
Clickable elements too close together