The sign() CSS function contains one calculation, and returns -1 if the numeric value of the argument is negative, +1 if the numeric value of the argument is positive, 0⁺ if the numeric value of the argument is 0⁺, and 0⁻ if the numeric value of the argument is 0⁻.... Syntax css /* property: sign( expression...Otherwise, returns NaN . Formal syntax <sign()> = sign( <calc-sum>...