Mouse Over Text Not quite aligned

[Teeser]

Dear All, can anyone help me solve this long standing issue.

I have a menu link. It's a big font. When you mouse over it simply changes colour from white to light blue.

However, the mouse-over (light blue) does not quite cover the White. See below:



Not sure it that attached or not?

Both fonts are exactly the same size. The light blue one is on the mouse over layer. Pasted exactly on top of the white one.

As you can see from the image above the is a little bit of white popping out of the bottom?

Any idea how to fix this?

Many thanks.