when you say seller details font, do you mean your shipping, payment, about us etc. info? the descrip. you write yourself? if you want to change that, click on 'profiles' then go into 'manage seller details'... then click 'edit' on whatever details you're talking about... then click the 'switch to design editor' on top.. you can then change all your font details, just like you do in your item description. hope this helps!!
edit/// and btw, i love the new temps too! very nice.