in folder css
you find a file named custom.css
with this content:
/*****************************************************
* 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 {
}
There you can add anything you want to. In your example you could add this below the current content, not inside the body part!
.MMM-Fuel {
width: 200px;
}
Play around with the numbers to adjust to your layout