/// - If a pixel value is passed, it will be converted to an em value using `$global-font-size` as the base.
/// - If a rem value is passed, the unit will be changed to em.
/// - If an em value is passed, the value will be used as-is.
+/// - If a list is passed, the mixin will iterate through the values in the list and function as described above.
///
-/// @param {Keyword|Number} $value - Breakpoint name, or px, rem, or em value to process.
+/// @param {Keyword|Number|Array} $value-list - Breakpoint name, px/rem/em value to process, or a list containing either.
///
/// @output If the breakpoint is "0px and larger", outputs the content as-is. Otherwise, outputs the content wrapped in a media query.
@mixin breakpoint($value-list...) {