$zindex-props: (
    'z-auto': 'auto',
    'z-0': 0,
    'z-1': 1,
    'z-2': 2,
    'z-3': 3,
    'z-4': 4,
    'z-5': 5
) !default;

@include style-class('z-index', $zindex-props, true);