I’ve a child Twenty Twenty-One theme and I want to make the content area in full with. I don’t want to use any plugin. I’ve searched and found that adding following code in CSS may work but for me it’s not working.

How to do it with css if it is possible?

.entry-content > 
*:not(.alignwide):not(.alignfull):not(.alignleft):not(.alignright):not(.is-style-wide) {
max-width: 87rem;
width: calc(100% - 8rem);
}