Functional units for Padding, Margin, Font Size, etc: Clamp() and Calc(). Clamp is very useful for desktop to mobile because you can change the unit size smoothly based on the width of the screen which always you to remove a lot of breakpoints. https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Functions#math_functions – Could also just have a free text box mode for CSS units for future compatibility with CSS standard changes.