Twenty Twenty: Wide and Full Width blocks top and bottoms margins don't respect original design causing layout issues

[collet]

In the original design:

• wide width blocks had vertical margins of 4rem on small devices, 6rem for @media (min-width: 700px) and 8rem for @media (min-width: 1000px)
• full width blocks had vertical margins of 5rem on small devices, 6rem for @media (min-width: 700px), 8rem for @media (min-width: 1000px) and 10rem for @media (min-width: 1220px)

Currently:

• wide width blocks have vertical margins of 4rem on all screen sizes
• full width blocks have vertical margins of 5rem on all screen sizes except 10rem for @media (min-width: 1220px)

The correct values don't appear because there is an error in the CSS declarations at the lines below. While they intend to set the margins, they do nothing as complex selectors can't be set in the :not() pseudo-class (​https://developer.mozilla.org/en-US/docs/Web/CSS/:not)
​https://github.com/WordPress/WordPress/blob/master/wp-content/themes/twentytwenty/style.css#L5255-L5259

.entry-content > .alignwide:not(.wp-block-group.has-background),
.entry-content > .alignfull:not(.wp-block-group.has-background) {
    margin-bottom: 6rem;
    margin-top: 6rem;
}

​https://github.com/WordPress/WordPress/blob/master/wp-content/themes/twentytwenty/style.css#L5901-L5905

.entry-content > .alignwide:not(.wp-block-group.has-background),
.entry-content > .alignfull:not(.wp-block-group.has-background) {
    margin-bottom: 8rem;
    margin-top: 8rem;
}

it's important to set these margins back to their original values because currently 2 consecutive wide columns blocks don't display properly (because the negative margin-top calculation for the second columns block was based on the original margin values ​https://github.com/WordPress/WordPress/blob/master/wp-content/themes/twentytwenty/style.css#L5756-L5759).

[sabernhardt]

Related: #49435