<li> tags in nav bar wrap to next line for French

[ysim]

On Chrome and Firefox anyway.

[kayzhu]

I noticed this too and made a failed attempted at fixing it in a766888020bdb174abf4ce065f7165f45255a060.

One way I can think of to fix it is by centring the entire

, and decrease the margins such that:

1. no overflow would occur for either lang
2. the nav bar is centered for both lang