Adobe Clean with Adobe Clean Serif in action on blog.typekit.com

Under the hood

.header-1 { font-family: adobe-clean, helvetica, arial, sans-serif; font-size: 62px; font-style: normal; font-weight: 900; letter-spacing: normal; line-height: 66px; text-transform: none; color: #FFFFFF; }
.header-2 { font-family: adobe-clean, helvetica, arial, sans-serif; font-size: 12px; font-style: normal; font-weight: bold; letter-spacing: 1px; line-height: 22px; text-transform: uppercase; color: #FFFFFF; }
.content-1 { font-family: adobe-clean, helvetica, arial, sans-serif; font-size: 18px; font-style: normal; font-weight: 300; letter-spacing: normal; line-height: 24px; text-transform: none; color: #747474; }
.content-2 { font-family: adobe-clean, helvetica, arial, sans-serif; font-size: 18px; font-style: normal; font-weight: 300; letter-spacing: normal; line-height: 30px; text-transform: none; color: #333333; }
.content-3 { font-family: adobe-clean-serif, georgia, serif; font-size: 22px; font-style: normal; font-weight: normal; letter-spacing: normal; line-height: 33px; text-transform: none; color: #333333; }
.content-4 { font-family: adobe-clean-serif, georgia, serif; font-size: 16px; font-style: italic; font-weight: 300; letter-spacing: normal; line-height: 24px; text-transform: none; color: #FFFFFF; }