in action on encoding.com
.header-1 {
font-family: Ubuntu;
font-size: 24px;
font-style: normal;
font-weight: bold;
letter-spacing: normal;
line-height: 28px;
text-transform: none;
color: #424242;
}
.header-2 {
font-family: Ubuntu;
font-size: 24px;
font-style: normal;
font-weight: 300;
letter-spacing: normal;
line-height: 28px;
text-transform: none;
color: #424242;
}
.header-3 {
font-family: Ubuntu;
font-size: 18px;
font-style: normal;
font-weight: 300;
letter-spacing: normal;
line-height: 22px;
text-transform: none;
color: #424242;
}
.content-1 {
font-family: Ubuntu;
font-size: 14px;
font-style: normal;
font-weight: 300;
letter-spacing: normal;
line-height: 19px;
text-transform: none;
color: #232323;
}
Ubuntu is available from Font Squirrel, Google Web Fonts and Typekit.
Found by @mikesten on 3 Nov 2016.