font family avenir 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

.serif_font {
	font-family:"Times New Roman", serif;
}
.sans_serif_font {
	font-family:"Open Sans", sans;
}