A) you have compression turned on, to make changes, you should disable it, make the changes, then re-enable it.
The JF! css file is located here:
modules/mod_jflanguageselection/tmpl/mod_jflanguageselection.css
You may consider moving some stuff around, according to ?tp=1 added to your URL, the logo is on the 'drawer' position. Yo can place a Module there but it's best reserved for System Messages (other wise they get lost somewhere down the page).
C) I would unpublish (through the Template Manager or Module Manager) the Menber Login, Text Size, and Language Selection to see if the Menu tightens up and looks good.
After that, move stuff around a bit to see how it looks, the logo in the default position or a Custom HTML published lower down the page..
(You could also adjust the JF! css and see if you are satisfied with the results.)