Borders disappear with "transform: scale..." in Firefox. How to fix it?

Question

There is transform: scale(0.9); , used for a body tag. In Firefox it causes a problem with the borders - parts of them "disappear" - usually a top or a left one. How to fix it?
Thank you in advance.

P.S. It's not allowed to use a large border.

Answer 1

border-width: 3px;