Why won't this stretch?

[Esquibb96]

Hi there, so i'm trying to learn as I go however i'm trying to make this product description bit full width. When I use margin-left: -20px it shifts to the left (great), but when I use margin-right -20px it doesn't move. 

[suyash1]

@Esquibb96 - add this css to the end of index.css file and check 

@media (max-width: 40em){
.product__details {padding: 0;}
}

[Esquibb96]

Just added it but it reduced the padding inside the box if that makes sense

[suyash1]

yes, around that box you have padding for container, if we remove that all
the text will be from end to end, will not look good