borders shrinling the content area: Help required !!

Hey – Am a non techie and need your help here.

please take a look at my blog: https://startnonprofitorganization.com/

The main content area has suddenly shrunk since today evening – the grey border has taken excessive space from left & right sides – shrinking and eating on the content area – making the page look very ugly.

It looks distorted in both firefox & IE. Strange because i did not even edit any code and it was all good till yesterday.

Any tips would be greatly appreciated ??