An element with class .shadow-8 shall feel like being 8px distant from the background along the Z axis. Same goes for the other shadows.
Increase contrast using a subtle inner/outer shadow, typically used with user-provided images that may or may not have a high contrast relative to the background.
It's best to use .shadow-contrast-inset on images. Notice how it affects light areas only.
The utility .shadow-contrast may feel like adding a subtle blur around areas where the image is only slightly darker than the background. It's best when the background is darker than the image (or whatever foreground element is used).
