Serif and sans serif are generic fonts.
If we need to display the text in a specific font,
we have to instead use actual font names
such as Arial or Times New Roman.
However, not all fonts are available on all browsers.
So, we need to specify fallbacks.
We can provide as many fallback
choices as we need separated by commas
in the font-family property.
The first available font in the
browser gets used.
Since, generic font families
are available on all browsers,
it's a smart choice to include
one as a fallback. Just remember
to make it the last one in the
list.