Seems to work as expected for me. I set the Div 1140px class to width:100% in the tablet and it stays like that in the tablet. It doesn’t affect the 1140px width in the laptop.
Tablet:
Laptop:
I personally think it’s not a great idea to use this 1140px div method. You make it more spacious for bigger screens but there’s a window of screens that cut off the content (like 960px). I recommend using this method to “activate” that media query: