Description : Purpose and use of functions in SASS.
Answer :
SASS functions are used to perform operations and return values that can be used in your stylesheets. You can use built-in functions like `lighten()` or `darken()` to adjust colors, or define your own custom functions. For example:`@function calculate-rem($px) { @return $px / 16px + rem; }` helps in converting pixel values to rem units.