try bringing back the radial shadow behind logo

[mpilosov]

now the particle animation is a thing, make the menu a bit easier to read.

[mpilosov]

currently have it behind site name only, which seems to suffice.

in order to make the background interactive, the header div became minimal width/height, so the radial effect doesn't quite work the same way. either sacrifice interactivity and get a good radial background, or keep it and just have the "mathematicalmichael" part with a contrast.