The background color of this paragraph should turn to green when the mouse pointer hovers either its text (here) or its whitespace background, here:

The cells in | this table | should go
green when | you hover | the pointing
device over | them (here). |
The rows in | this table | should go
dark green | when the | pointing device
is over the | five pixel | border spacing
and when it is | over the cells. |
Including here, |  | blank cells.