Source Sans Pro with Work Sans in action on relonch.com

Under the hood

.header-1 { font-family: "Work Sans", Arial, sans-serif; font-size: 45px; font-style: normal; font-weight: 300; letter-spacing: normal; line-height: 50px; text-transform: none; color: #43484F; }
.content-1 { font-family: "Source Sans Pro", Arial, sans-serif; font-size: 20px; font-style: normal; font-weight: 300; letter-spacing: normal; line-height: 27px; text-transform: none; color: #43484F; }
.content-2 { font-family: "Work Sans", Arial, sans-serif; font-size: 14px; font-style: normal; font-weight: 600; letter-spacing: normal; line-height: 33px; text-transform: uppercase; color: #FFFFFF; background-color: #43484F; }
.content-3 { font-family: "Work Sans", Arial, sans-serif; font-size: 18px; font-style: normal; font-weight: normal; letter-spacing: normal; line-height: 23px; text-transform: uppercase; color: #43484F; }