post content line-height was not large enough

when converting to px values from em the line-height got messed up and set at 14px for .content which is almost no line-height given the 13px text size, it should be 18px also the .content class has a font-size of 10px that is always overridden by a componud selector .postbody .content so might as well just make it 13px here as well.