src: url('#') format('...');
Like mentioned previously,
font-family: can be used for generic font classes (serif, sans-serif, and monospace) and also for specific font family names.
@font-face, fonts can be named in relation to their files. This can be the same for the whole family (i.e.
font-family: 'Playfair Display') or specific to different variations (i.e.
font-family: 'Playfair Display Bold') depending on how the rule is structured.