Avenir font family code example

Example 1: font family system

/* System Fonts as used by GitHub */
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
}

Example 2: css font family

/* You can set the font family by using font-family: followed by the font family name
 If you want to use a google font you have to find it on the google font website
then link the script in your HTML and then put the name in font family 

browse fonts:
https://fonts.google.com/
*/

.class {
  font-family: sans-serif
}