Generate a CSS box-shadow value

Build a copy-ready CSS box-shadow value from five explicit inputs instead of assembling the syntax by hand. Provide horizontal and vertical offsets, a blur radius, a spread radius, and any supported CSS color value. The generator validates the numeric fields, rejects negative blur or spread values, and returns a consistently formatted shadow using pixel units. It is useful for interactive design work, design-token pipelines, component generators, and tests that need the same output from the same input every time.

Set the shadow position with horizontal and vertical offsets

Both values are expressed in CSS pixels in the generated result. A positive horizontal offset moves the shadow toward the right, while a negative value moves it toward the left. A positive vertical offset moves it downward, while a negative value moves it upward.

Zero keeps the shadow centered on that axis. These fields may be decimal values when a design system uses fractional spacing, and the generator preserves the validated numeric value rather than silently rounding it. Think about the apparent light source when choosing offsets: a light above and to the left usually produces a shadow below and to the right.

Small offsets tend to feel close and subtle, whereas large offsets can make an element appear elevated or deliberately graphic. The tool does not infer direction from blur, color, or component type, so the values remain under your control and can be reproduced exactly across stylesheets and builds.

Control softness and footprint with blur and spread

The blur radius controls how gradually the shadow transitions from its strongest area into transparency. A value of zero creates a hard edge, while larger values create a softer and visually wider shadow. The spread radius expands the shadow shape before blur is applied.

Zero follows the element's original shadow footprint, and a positive spread makes the footprint extend outward on every side. Enter each value as a plain number; the returned CSS adds px units in the required order. Blur and spread are different controls, so increasing one is not a substitute for increasing the other.

For a restrained interface shadow, pair a modest offset with moderate blur and little or no spread. For a strong focus ring or poster-like effect, zero blur and a larger spread can produce a crisp outline. Preview the result against the actual surface because perceived softness changes with contrast and surrounding colors.

Choose a color and apply the generated value

The color field accepts one nonempty CSS color value, including a named color, hexadecimal notation, or a functional form such as rgb() or hsl(). Alpha transparency is often important for natural shadows because an opaque dark color can look heavy on light surfaces and muddy on colored backgrounds. The generator trims unnecessary surrounding whitespace, checks balanced parentheses, and rejects declaration-breaking characters.

Assign that value to the box-shadow property, place it in a custom property, or store it as a design token. The response is a value rather than a complete declaration, so your application still chooses the selector and whether to combine it with other shadow layers. For multiple shadows, generate and review each layer separately before joining the values with commas.

Execution is deterministic and has no network, model, randomness, storage, or clock dependency, which makes the output suitable for snapshots and repeatable build automation.