First off, Democrats won the majority of the House races, which would be the first hint that maybe the also won the majority of the vote. Secondly, because of gerrymandering, to win the majority of the House races, they had to win a supermajority of the popular vote. They win races that they win by more votes than Republicans do due to gerrymandering.
I think Arminius is having trouble understanding the difference between winning fewer races than in the last very successful year, and losing most of the races. Democrats won the majority of the House races. They may also win a majority in the Senate.
What three predictions did I make?
1) Democrats would keep the House, and they did that.
2) Biden would almost certainly win. There was a very slight chance trump could win, but it was extremely doubtful. Biden won.
3) Democrats had a 50/50 chance of winning the Senate. They still have a chance of winning, but it is less than 50% chance now. Maybe a 20% chance.