Mochikoro

Mochikoro is a logic puzzle from Japan. The objective is to blacken certain cells to create rectangular white regions in specified areas.

Rules: Colour the neutral cells of the grid black or white. The black cells cannot cover an area of size 2×2 and divide the grid into rectangular areas of orthogonal white cells.
Every cell with a number belongs to a white area, and at most one cell with a number belongs to a white area. The number indicates the number of cells in the white area. White areas without numbered cells can be any size.
The white areas must not touch each other orthogonally, but they must be connected diagonally.