Add CSS custom properties

[sntran]

Would you consider add them in so others who use the minified CSS can still reference the variables?

Something like this:

reflex/less/reflex/_variables.less

Lines 46 to 60 in b32a2fe

	:root {
	--reflex-prefix: @reflex-prefix;
	--reflex-columns: @reflex-columns;
	--reflex-grid-spacing: @reflex-grid-spacing;
	--reflex-xs: @reflex-xs;
	--reflex-sm: @reflex-sm;
	--reflex-md: @reflex-md;
	--reflex-lg: @reflex-lg;
	--reflex-xlg: @reflex-xlg;
	--reflex-xxs-max: @reflex-xxs-max;
	--reflex-xs-max: @reflex-xs-max;
	--reflex-sm-max: @reflex-sm-max;
	--reflex-md-max: @reflex-md-max;
	--reflex-lg-max: @reflex-lg-max;
	}

[leejordan]

yes I think this is a good request and I will do it when I have time unless somebody else gets there first