Typography is all about style, proportions, and spacing. Good typography is not only imperative for aesthetic appeal, but it also improves site usability when text legibility and readability concepts are applied.
Typography is also about emotion. Do the letters complement your content, or contradict it? Even when typography is applied to the same text, it can make different people feel different things. Therefore, being ​deliberate about typography lets us control these feelings.
Note: When using multiple values, the list of font families defines the priority in which the browser should choose the font.