She's a persecuted little Mary Sue white girl living in a post-apocalyptic world populated by cardboard-cutout people (and the protagonist's dad, who is a calculator with a side-order of insanity), where some stupid shit that is never really explained happened, and now white people fucking die of something shit-scary but not explained real quick if they get exposed to sunlight. Meanwhile, people with more melanin magically don't, so in a world where resources are so scarce that girls get cut off and shoved outdoors on their 18th birthday if they haven't found a man (WHAT), the white people just said, "Fuck it, I'm dead and shit." and put black people in every position of power (because that's TOTALLY what happens when a society where white people overwhelmingly run things realize that black people can do the huge amounts of work that need to be done to keep things running for them).
So it's a TOPSY-TURVY CRAZY ASS WORLD, where everybody hates everybody, and every culturally-defined "racial" group has a mineral name (white=pearl, black=coal[WHAT], asian=tigereye, hispanic=oh god I forget please don't make me read this thing again please I beg of you), and black people are in charge on account of having the most melanin, and have been for a while, yet seem to be living out white stereotypes of black people (in fact, EVERY minority is a walking stereotype).
SO, because everybody hates everybody, and because white people are the lowest of the low for being likely to die if they get some sun -- in a society that lives underground now -- all white people are expected to look as black as they can manage. Which means blackface, complete with tons of red lipstick and Poor Little White Girls trying to get "curvy" in a society where everyone is strictly rationed, yet somehow those black girls still are stereotypically big in all the stereotypically right places.
Oh, and tons of white self-loathing, which is COMPLETELY different from teenage girl self-loathing and feeling-sorry-for-oneself angst, I'M SORRY, if you can't tell the difference, because IT'S SO NOT THE SAME.
[And this is before the book gets going on what passes for the plot]
But the author IS NOT A RACIST, because she says she is color-blind and teaches her children the same, which is so NOT doublespeak for "the only aspects of culture and issues and contributions worth giving a shit about are MINE, the white person's", that it is CRAZY.
But really, it's all just crazy.