Admin interface

Hi all,
First of I am not sure if this is the correct category for this questions. If not I apologise.

- My firts question is how can I correct the colour of the shops, menu (System, Products, Customers...).
On Joomla 3 it is a dark blue and the text doesn't display well (please see img attached).

- The second, what is the best way to simplify the admin view? I mean, once the shop is configured, shipping method, currency, etc.
It is not something that the client will change often. If they do, they can come to me to get that changed. So how would be the best way to customised the admin view for that specific user?
I just want to make day to day interface that the client uses more straight forward.

Thanks

Thanks

-- url of the page with the problem -- : mywebsite.com/mypage
-- HikaShop version -- : HikaShop Essential: 2.3.0
-- Joomla version -- : Joomla 2.3.3
-- PHP version -- : 5
-- Browser(s) name and version -- : FF 29.0.1
-- Error-message(debug-mod must be tuned on) -- : Error_message