My hotmail account is showing small how do i make it bigger?

I have hotmail which is now outlook and have had it since it was hotmail and never had problems with it till today..Today i was online composing and email
when suddenly without warningthe print on the page go very small so much so that i couldnt read what i had written..I did nothing but compose a email..
i tried to fix this but coudnt ..Though it was my computer but this is the only site that is affected..and it its till showing up this way..I was wondering what went wrong?Could you please help?Thanks
shells