How to make proper shorthand notation of attached font properties?

Question

css

Dmitrijs Balcers url(' https://fonts.googleapis.com/css?family=Open+Sans:... ');
Added a font. How to correctly write in a short note that this font is 28px in size, Open Sans Regular
And in general, which css property corresponds to Open Sans and which Reaular?

Answer 1

.font{
font: 400 28px 'Open Sans', sans-serif;
}

regular is font-weight: 400;
Light is font-weight: 300;
by default, you can not set regular, but simply write

.font{
font: 28px 'Open Sans', sans-serif;
}

Answer 2

Em?