I would also like to point out that if you are using a border on your menu, you should take that into account when you edit the margin-left:50px;
If you have a border of 5px you should change the margin-left to 48px. Meaning, what ever your border width is you should subtract that from the margin-left.

If you do not have a border, the 50px will work just fine.

Hope this helps!
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