Source Sans in action on hey.com

Under the hood

.header-1 { font-family: "Source Sans Variable", "Helvetica Neue", helvetica, "Apple Color Emoji", arial, sans-serif; font-size: 43px; font-style: normal; font-weight: 700; letter-spacing: normal; line-height: 54px; text-transform: none; color: #222222; }
.header-2 { font-family: "Source Sans Variable", "Helvetica Neue", helvetica, "Apple Color Emoji", arial, sans-serif; font-size: 32px; font-style: normal; font-weight: 700; letter-spacing: normal; line-height: 41px; text-transform: none; color: #0970B7; }
.content-1 { font-family: "Source Sans Variable", "Helvetica Neue", helvetica, "Apple Color Emoji", arial, sans-serif; font-size: 21px; font-style: normal; font-weight: 400; letter-spacing: normal; line-height: 32px; text-transform: none; color: #222222; }
.content-2 { font-family: "Source Sans Variable", "Helvetica Neue", helvetica, "Apple Color Emoji", arial, sans-serif; font-size: 21px; font-style: normal; font-weight: 400; letter-spacing: normal; line-height: 32px; text-transform: none; color: #0970B7; }