Yes, the white on black is fine. I checked the #8a7ae2 purple (http://webaim.org/resources/contrastchecker/ http://webaim.org/resources/contrastchecker/) and, s

Yes, the white on black is fine. I checked the #8a7ae2 purple (http://webaim.org/resources/contrastchecker/ http://webaim.org/resources/contrastchecker/) and, surprisingly, it passes WCAG AAA guidelines. I say "surprisingly" because it hurts my eyes. I think jumping between the alternating white and purple is what does it.