Logo grid and other small issues

Hi,

I have really tried, but don’t understand why I can’t have more than 2 columns within the logo grid. I have tried 3, 4 ot 5 columns. Smaller logos etc… but only two columns appear :

http://fredwps-global-media-holding.pf2.wpserveur.net/presse/

Other issue : the search form looks very bad on safari. Can’t attach mage but it’s really bad and white text color on white bg.

And, how to add the search option on the mobile menu ?

Regards