/**
 * Return the Map properties representation for the rhythme width
 * The rhythme width is the width of an element that target a certain number of letters by line
 *
 * @param 			{Integer} 			[$letters-count=settings.typography.line-letters-count] 		The number of letters to target by line
 * @return 			{Map} 																		The Map properties representation
 *
 * @example
 * s-rhythm-width(50);
 * // return
 * // (
 * // 	display : block,
 * // 	max-width : 50ex
 * // )
 *
 * @author 			Olivier Bossel <olivier.bossel@gmail.com> (https://olivierbossel.com)
 */
@function s-rhythm-width(
  $letters-count: s-setting("typography.line-letters-count")
) {
  @if unitless($letters-count) {
    @return (display: block, max-width: $letters-count + ex);
  } @else {
    @return (display: block, max-width: $letters-count);
  }
}