Main forum font

[Dark Navi]

Ok so I am trying to set Tahoma 11pt as my main forum font;

https://vborg.vbsupport.ru/external/2012/04/42.jpg

as it is currently this, frankly ugly, Verdana? 13pt Font;

https://vborg.vbsupport.ru/external/2012/04/43.jpg

How do I go about changing it so the change reflects across the whole forum?

[Amaury]

Style Variable Editor for chosen style > Global category > Font

[Dark Navi]

Many thanks for that pal, greatly appreciated.