The font size and type are controlled by configuration parameters inside the web project. The parameter for changing the font size is called basefontsize and the parameter for the font type is baseFontFamily.
To modify the font size in IT Shop:
To modify the font type:
The following screenshot shows an example of those two fields having been customised:
Once a change has been made to one or both of these parameters, the changes must be published before they will take effect.
Please note that the basefontsize parameter will modify the scale of all text in the IT Shop.