Variable fonts are an evolution of the OpenType font specification that enables many different variations of a typeface to be incorporated into a single file, rather than having a separate font file for every width, weight, or style. They let you access all the variations contained in a given font file via CSS and a single @font-face reference. This article will give you all you need to know to get you started using variable fonts....separate files for 'Roboto Regular', 'Roboto Bold', and 'Roboto...need at least four files: regular, italic, bold, and bold italic...