@airart I run a different module called MMM-TextClock (similar name) in full screen as my first page.

To display it in full screen I had to add following code into

custom.css /* MMM-TextClock --------------------------------------------*/ .L12Field { width: 100%; height: 100%; font-family: Roboto; font-size: 125px; line-height: 135px; font-weight: 100; color: #333; }

Give it a try and see if it works for you.