CSS Shadow Generator

For realistic drop shadows on cards, use these principles: Start with small Y-offset values (2-8px) to simulate light source angle from above. Set blur radius roughly 2-3x the Y-offset for natural softness (e.g., offset 4px with blur 10-12px). Use subtle spread (-1px to 2px) to control shadow size without affecting element dimensions. Choose low opacity colors (0.1-0.3 alpha) rather than pure black for natural appearance. Dark grey (#000000 with 10-30% opacity) often works better than pure black. For card elevation effects, layer 2-3 shadows with increasing blur and decreasing opacity: first shadow sharp and close (Y: 2px, blur: 4px, opacity: 0.15), second shadow softer and further (Y: 8px, blur: 16px, opacity: 0.1). This creates the multi-stage depth seen in Material Design. Test on both light and dark backgrounds—shadows should be visible but not distracting. Adjust opacity higher for light backgrounds (20-30%) and lower for dark backgrounds (10-15%) to maintain contrast balance.

Each shadow property serves a specific purpose in creating the desired visual effect: Horizontal Offset (X): Moves shadow left (- values) or right (+ values). Positive values simulate light from the left, negative from the right. Typical range: -20px to 20px. Vertical Offset (Y): Moves shadow up (- values) or down (+ values). Positive Y (most common) simulates overhead light source. Negative Y creates unnatural underlit effects. Typical range: -20px to 30px. Blur Radius: Controls shadow softness/edge fuzziness. 0px = sharp, hard shadow. Higher values = softer, more diffuse shadow. Should generally be 2-4x the offset value for natural appearance. Typical range: 0-50px. Spread Radius (box-shadow only): Expands (+) or contracts (-) the shadow size. Positive values make shadow larger than element, negative make it smaller. Useful for creating ambient glow effects without affecting element layout. Typical range: -10px to 20px. Color: Includes hue, saturation, lightness, and alpha (opacity). Use HSLA or RGBA format. Lower opacity (0.1-0.3) creates subtle shadows, high opacity (0.5-0.8) creates dramatic/unnatural shadows. Shadow Type: 'outset' (default) creates external shadow, 'inset' creates internal shadow for embossed/depressed appearance (useful for form inputs, pressed buttons). All values can be adjusted with slider controls for precise control, with real-time numeric display.

Inset shadows create the illusion that an element is recessed into the page (pressed button, active form input, engraved text). Use the 'inset' keyword: box-shadow: inset X Y blur spread color;. For depressed button effect: Use small negative offsets (X: -2px, Y: -2px) to create shadow from top-left corners. Add slight blur (2-4px) for softness. Use low opacity (0.2-0.3) dark colors. Combine with non-inset shadow for unpressed state—toggle between them on :active pseudo-class. For form input focus states: Inset shadow (inset 0 0 0 3px rgba(...)) creates colored border/glow effect without affecting layout (better than border for transitions). For engraved text effect: Use text-shadow with positive offset (text-shadow: 1px 1px 1px rgba(255,255,255,0.5)) on dark text for chiseled appearance. Or use negative offset on light text. For card containers with content: Inset shadow can create vignette effect (inset 0 0 20px rgba(0,0,0,0.3)) for depth at edges. Note: Inset shadows don't work with text-shadow, only box-shadow. Inset shadows appear inside the element border, not outside.

Absolutely. All shadow generation and preview happens entirely locally in your browser using client-side JavaScript and CSS. No data is transmitted to any server during your design process. Your shadow configurations, color choices, and design parameters never leave your device. This client-side architecture ensures complete privacy for sensitive design work, proprietary UI systems, and pre-release product designs. No network requests are made to external services, no analytics tracking is performed on your design choices, and no user accounts or authentication is required. Unlike cloud-based design tools (Figma, Sketch, Adobe XD) which store designs on cloud servers (potentially accessible to employees or vulnerable to data breaches), our tool keeps everything local. Once you're satisfied with a shadow, you simply copy the generated CSS code and paste it into your project's stylesheet. The copied code contains only standard CSS properties with no proprietary formats or licensing restrictions. For additional security in corporate environments, you can use this tool offline (once the page is cached) or in air-gapped networks. Your creative process remains completely confidential from concept to implementation.