font-weight: calc(300 + 400) => 700
font-weight: calc(700) => 700
font-stretch: calc(50% + 25%) => 75%
line-height: calc(1em + 6px) => 26px
line-height: calc(2 * 1.5) => 60px
line-height: calc(50% + 50%) => 20px
font-size: calc(10px + 20px) => 30px
font-size: calc(50% + 50%) => 20px
font-size: calc(1em + 5px) => 25px
