Colour carries the page, not white space.
Three saturated grounds — maroon, wine and gold — do the work that margins do elsewhere. A light display serif floats on top of them, one gold marks every action, and nothing is rounded.
A page is a sequence of full-bleed bands. Where another system would divide sections with a rule, this one changes ground — maroon, wine, gold, gainsboro, and white where a run of colour needs a rest — and lets the colour boundary do the dividing.
The display serif is Light — weight 300 — and it is usually white on a dark band. That combination is fragile: at 300 on maroon, anything below about 28px starts to disappear, which is why the ramp stops there and everything smaller is Lato.
Every button fill is gold, and gold appears as type only on a dark band. The reds are grounds rather than fills — which is the one thing that keeps a palette with three reds in it legible.
Kepler Std and Alverata are licensed; Crimson Pro and Alegreya Sans stand in for them. Lato is the real thing. And Alarm is an added error colour: the site styles error and success messages identically, both plain black, so it has no error colour of its own to lift. Both are marked in the README.