Open Sans in action on canva.com

.header-1 { font-family: 'Open Sans', 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 43.2000007629395px; font-style: normal; font-weight: 300; letter-spacing: normal; line-height: 51.8400001525879px; text-transform: none; color: #3F4652; }
.content-1 { font-family: 'Open Sans', 'Helvetica Neue', Helvetica, Arial, sans-serif; font-size: 14.3999996185303px; font-style: normal; font-weight: normal; letter-spacing: normal; line-height: 21.6000003814697px; text-transform: none; color: #3F4652; }
Open Sans is available from Font Squirrel, Google Web Fonts, MyFonts and Typekit.

Try this combination out in Pair and Compare.
Found by @mikesten on 12 Aug 2015.

Liked by:
@mikesten @AmaliaShacharr

Open Sans