I am attempting to achieve an effect where a div appears to fade into the background of the content. The concept involves having a simple border: 1px #000 solid; on the top and bottom of the div, along with a large inset shadow on the left and right sides to give the illusion that the div extends back behind the page, as if there is a slit in the background allowing the div to pass through.
Currently, box-shadow applies to all sides simultaneously. Therefore, I need a method to create a substantial shadow on the left and right while still being able to interact with the content beneath the shadow. This is the beauty of CSS shadows - they allow interaction with the underlying content. Using an image would not work because it would obstruct interactions below it.
One individual on this post recommended using border-image by incorporating a CSS3 gradient into it. Understanding this concept confuses me as I attempt to implement a CSS3 gradient on one side of a div's border.
Can anyone provide assistance?
Here is the webpage for reference, specifically regarding the image slider section: