The CSS box-shadow property paints one or more shadows around an element without changing document layout. ShadowStack exposes only values that appear in the copied declaration, so the browser preview and source remain directly comparable. Each layer keeps its explicit paint order, inset state, four pixel lengths, hexadecimal colour and opacity.
Read the first layer as the top shadow
A comma-separated box-shadow list is ordered: the first shadow is painted on top of the following shadows. This matters when opaque or inset layers overlap. ShadowStack keeps the visible tabs in exactly the same order as the copied CSS. Move Up exchanges the selected layer with the previous one; Move Down exchanges it with the next one. Neither action recalculates colour, blur or geometry. Compare the code after every move and use a small, darker top layer over a wider, lighter lower layer when you want controlled depth instead of one very large blur.
Keep every layer explicit and bounded
The generator accepts one to eight layers. Add Layer inserts a documented neutral outer shadow immediately after the selected layer, making the resulting position predictable. Removal stops at one layer so the declaration always remains valid. Each layer owns independent inset, offset, blur, spread, colour and opacity values; there is no hidden global light source or automatic scaling. If the result needs more than eight layers, simplify the effect or maintain the final CSS directly, because a large synthetic stack becomes difficult to review and can add unnecessary paint work.
Verify the CSS in its real component
ShadowStack renders the copied declaration with the current browser engine, but the preview is not a compatibility or accessibility certificate. Paste the property into the intended component and test every supported browser, responsive width, background and overflow container. A broad blur may be clipped by an ancestor and an inset shadow may cover content or focus indicators. Inspect keyboard focus at every state, measure text and control contrast with a dedicated tool, and retain a usable border or other non-shadow distinction when the interface depends on clear boundaries. The capsule stores no presets or history, so keep accepted CSS in your own source-controlled stylesheet before reloading.