Need a solution. Appearing and disappearing block?

Question

css

Very urgent advice needed. The next task is I have a menu in a separate block (block 1). A drop-down separate block (block 2). So the essence of the task is that when you hover over "block 1", "block 2" should appear, and at the same time, while we drive along "block 2", so that it does not disappear.
clip2net.com/s/3nLkQu7
A visual principle of operation can be seen here when you hover over the product catalog, a menu appears. Need the same.
vitebsk.biz
Where to even dig?)

Answer 1

JS: onmouseover, onmouseout

Answer 2

In order to ensure that block 2 does not disappear when hovering over, you need to place block 2 in html inside block 1.

Answer 3

Use the :hover, :active selectors in block 1 properties for nested block 2