and then main.css to see how they are used

Did you ever get this working? I’m having exactly the same issue. I have the holiday countdown module. We’re off to Disney, so I thought it would be fun to put it in a Disney font. I’ve downloaded one and put it into a fonts folder under MagicMirror.
I have defined it with an @ statement, included the fonts/ source folder and file name, and added it to the countdown module, but it is still not changing the font for that module :(

body * {
  font-family: "SF";
}

That might get the job done, but there may be more specific rules you need to write to override in other cases. Try this and see how far it gets you.

/*****************************************************
 * Magic Mirror                                      *
 * Custom CSS                                        *
 *                                                   *
 * By Michael Teeuw http://michaelteeuw.nl           *
 * MIT Licensed.                                     *
 *                                                   *
 * Add any custom CSS below.                         *
 * Changes to this files will be ignored by GIT. *
 *****************************************************/

body {	
}

@font-face {
  font-family: "SF";
  font-style: normal;
  font-weight: 100;
  src:
    local("ComicRelief"),
    url("fonts/ComicRelief.ttf") format("truetype");
}

/home/pi/MagicMirror/fonts

And my custom css looks like this

 body {	
@font-face {
  font-family: "SF";
  font-style: normal;
  font-weight: 100;
  src:
    local("ComicRelief"),
    url("fonts/ComicRelief.ttf") format("truetype");
}
}

Despite that, font is not seen. What could be the reason?

@font-face {
  font-family: "Verdana";
  font-style: normal;
  font-weight: 100;
  src: url("/fonts/Verdana.ttf")  format("truetype");
}

That said, I’m not sure about TrueType support in Chrome, and subsequently Electron. if this still doesn’t work, you’ll need to convert the font into a supported format, such as woff or woff2. Font Squirrel is an online tool that can do it, but you might run into copy protection issues, as Verdana is a licensed font. Do a Google search for web font generator to find other options, or you can even try searching for a woff version of Verdana.

Of course, the designer in me is screaming that there are so many nicer type faces suitable for UI than Verdana that are available for free. Google Fonts has many options that are readily downloadable, and subsequently can be converted to web font formats using Font Squirrel.

Good luck!

@font-face {
font-family: Verdana;
font-style: normal;
font-weight: 100;
src:
local(“Verdana”),
url(“/home/pi/MagicMirror/fonts/Verdana.ttf”) format(“truetype”);
}

.newsfeed {
font-family: Verdana;
}

I wrote below but it didnt work

@font-face {
font-family: Verdana;
font-style: normal;
font-weight: 100;
src:
local(“Verdana”),
url(“/home/pi/MagicMirror/fonts/Verdana.ttf”) format(“truetype”);
}

.newsfeed {
font-family: Verdana;
}

So your code should instead be:

@font-face {
  font-family: Verdana;
  font-style: normal;
  font-weight: 100;
  src:
    local("Verdana"),
    url("/home/pi/MagicMirror/fonts/Verdana.ttf") format("truetype");
}

.newsfeed {
  font-family: Verdana;
}

This avoids using the local version of the Verdana font. Why not use the local Verdana font (or install your desired alternative) and use the below instead?

.newsfeed {
  font-family: Verdana;
}

I tried to change my newsfeed font and i added below commands to custom.css but it didnt work. What should i do ?

Thanks

.newsfeed {
  font-family: Verdana;
  font-style: normal;
  font-weight: 100;
  src:
    local("Verdana"),
    url("/home/pi/MagicMirror/fonts/Verdana.ttf") format("truetype");
}

But the main module class name are always the name of the module as put in the config file

.calendar for calendar
.alarm for alarm
.MMM-Instagram for MMM-Instagram

etc etc

.calendar

how i can find class (.calendar for your example) of any module to use that?

.calendar {
Font-family : YourFont;
}

That would change the font for the module calendar

@font-face {
  font-family: YourFont;
  font-style: normal;
  font-weight: 100;
  src:
    local("YourFont"),
    url("fonts/Yourfont.ttf") format("truetype");
}