A single box-shadow declaration produces a shadow that looks functional but rarely looks polished. If you've ever wondered why shadows in high-quality design systems look better than the ones you write from scratch, the answer is almost always multiple layers. Understanding how CSS handles layered shadows changes how you approach the property entirely. The Basic Syntax The box-shadow shorthand takes up to six values: box-shadow : offset-x offset-y blur-radius spread-radius color ; Enter fullscreen mode Exit fullscreen mode With an optional inset keyword at the front to flip the shadow inside the element: box-shadow : inset 0 2 px 4 px rgba ( 0 , 0 , 0 , 0 . 1 ); Enter fullscreen mode Exit fullscreen mode The only required values are offset-x and offset-y. Everything else has defaults: blur is 0 (sharp edge), spread is 0 (same size as element), color is the current color value.…