Congress is still winner-take-all for the individual seats. There is only one independent in the 535 Congressional seats, and that's just because he changed parties after he was elected. While there's a different distribution of those two parties, it's still just two parties. If there was proportional representation in the US, and 5% of the population voted for Libertarians, then there would be about 26 Libertarians in Congress. If 1% voted for them, there'd still be five. As it is now, one seems outrageous.