A stripe on the lip - if I understand it to mean that the forward edge of each step is outlined - gets my vote. In Juneau we have many outdoor stairs and although they are not striped as such - they are steel - still the pebbled outline is there, at the forward edge.

I have a small problem with differently colored steps- for some reason they make me feel somewhat dizzy, although I can override it. Feels kind of like having steps of different heights and depths.

Peace, in your link those concrete steps inside that concrete building are horrendous! One time that having carpeted stairs and maybe hanging pictures on the walls would not come amiss.