The margin that I see disappears after 1%, what does it mean?

Please explain margin to me. For instance, I take a $2,500 place with 10x leverage briefly, and I get $2,050 margin (I don’t quite perceive why it’s $2,050 and never $2,500).

Then two examples:

1. We see a drop to zero and the place closes. The account stability is $2,400 as an alternative of $2,500. And the margin decreases by $2,050 for a 1% transfer, not for 10%. Very quick. I don’t absolutely understand it. As a result of within the wallet there’s still a big quantity, the debt is repaid, and I’m only down $100.
2. We see the margin improve from $2,050 to $4,000, and in the wallet stability we see a $500 revenue — it turns into $three,000 after closing the trade and repaying the 10x leverage as properly. However we don’t see $four,000 in the stability, we see $three,000.

I don’t perceive this margin that’s displayed. And the way can I know when liquidation will begin?