Azul Silver – White border around my content and above footer and between heade

my website is https://www.firebirdclubofcanada.ca/

I’m sorry but i am a mechanic not a computer guy . I built this website over the past two weeks by trial and error ..lol

I have inserted dozens of different css codes i have found and nothing works trying to get rid of this white on my page around the content , the header , the footer etc.
Can some one tell me what custom css to add that will actually get rid of this on all my pages. Thank you very much in advance for your time and sensitivity to my ignorance concerning this wordpress code stuff !