Change font size for MMM-HTMLBox module

[evroom]

Module: MMM-HTMLBox
I want to use this simple but useful module, but how can I change font size for this module ?

I tried the custom.css

.MMM-HTMLBox {
font-size: 12px;
}

That does work, but now the spacing is rather large.
The module itself does not have a css file.

Someone who can guide me a bit ?

[evroom]

Some times Google is your friend:

custom.css

.MMM-HTMLBox {
font-size: 18px;
line-height: 22px;
}