Force page breaks before the element so that the next page is formatted as a left page. It's the page placed on the left side of the spine of the book or the back side of the page in duplex printing.
Force page breaks before the element so that the next page is formatted as a right page. It's the page placed on the right side of the spine of the book or the front side of the page in duplex printing.
If pages progress left-to-right, then this acts like left. If pages progress right-to-left, then this acts like right.
Page break aliases
The page-break-before property is now a legacy property, replaced by break-before.
For compatibility reasons, page-break-before should be treated by browsers as an alias of break-before. This ensures that sites using page-break-before continue to work as designed. A subset of values should be aliased as follows: