Text size, fonts and colours in Windows Live Mail

I have continuing eyesight problems following a series of operations.  I moved recently from BT Yahoo! mail to Windows Live Mail for security reasons.  However, I find I  need to increase the font size and colours of text in Live Mail in order to be able to use it effectively, not just message text but also header and drop-down menu text.  I have attempted to do this via MS articles on-line but each time I have carried out the procedure I find that the changes do not register.  This is  now a serious impediment to my being able to use Live Mail.  I've tried using Magnifier but it does not help me, I'm afraid.