I need to apply shadow to an overarching border, however so far I've created the shadow with CSS, and since the overarching border is formed by two boxes, the shadow overlaps.
My solution to this is to cover up the overlapping part with an image that looks like a seamless blend, however I'm not sure how the shadows should look, when they meet like that. Please see the blue circle area.
How can I figure out how the natural shadow blend would look for an example like this?
I can use Adobe Photoshop or GIMP to achieve this.