Source Sans in action on concisecss.com

.header-1 { font-family: source-sans-pro, 'Segoe UI', 'Myriad Pro', Helvetica, Tahoma, sans-serif; font-size: 72px; font-style: normal; font-weight: normal; letter-spacing: normal; line-height: 72px; text-transform: none; color: #FFFFFF; }
.header-2 { font-family: source-sans-pro, 'Segoe UI', 'Myriad Pro', Helvetica, Tahoma, sans-serif; font-size: 24px; font-style: normal; font-weight: 300; letter-spacing: normal; line-height: 24px; text-transform: none; color: #FFFFFF; }
.content-1 { font-family: source-sans-pro, 'Segoe UI', 'Myriad Pro', Helvetica, Tahoma, sans-serif; font-size: 18px; font-style: normal; font-weight: bold; letter-spacing: 1px; line-height: 23.9999389648438px; text-transform: uppercase; color: #161E27; background-color: #FFFFFF; }
.content-2 { font-family: source-sans-pro, 'Segoe UI', 'Myriad Pro', Helvetica, Tahoma, sans-serif; font-size: 18px; font-style: normal; font-weight: bold; letter-spacing: 1px; line-height: 23.9999389648438px; text-transform: uppercase; color: #161E27; background-color: #FFFFFF; }
Source Sans is available from Font Squirrel, Google Web Fonts and Typekit.
Created by @keenan_payne.

Found by @mikesten on 10 Jul 2015.

Liked by:
@mikesten @creativ_ely

Source Sans