Examples of websites using
Avenir
(Avenir is a sans-serif font designed by Adrian Frutiger and Nadine Chahine, released by Linotype in 1988. It features clean and modern letterforms and is available in multiple weights and styles)
with
Source Sans Pro
(Source Sans Pro is a Sans Serif font designed by Paul D. Hunt. The font family includes six styles, each with regular, italic, bold, and bold italic variations, providing a versatile range of options for designers)