dylantarre

shadow-scale

Generates layered box-shadow elevation tokens for depth hierarchy. Use when creating elevation systems, card shadows, modal depth, or dark mode shadow variants. Outputs CSS, Tailwind, or JSON.

dylantarre 24 3 Updated 5mo ago
GitHub

Install

npx skillscat add dylantarre/design-system-skills/shadow-scale

Install via the SkillsCat registry.

SKILL.md

Shadow Scale Generator

Overview

Generate consistent elevation scales using layered box-shadows. Creates depth hierarchy from subtle lifts to dramatic floats with proper blur, spread, and opacity progressions.

When to Use

  • Setting up elevation tokens for a new project
  • Creating card/modal depth hierarchy
  • Standardizing shadow styles across components
  • Building dark mode shadow variants

Quick Reference

Level Typical Use Character
none Flat elements No elevation
xs Subtle lift Barely raised
sm Cards, buttons Slight depth
md Dropdowns, tooltips Clear separation
lg Modals, popovers Floating
xl Dialogs, drawers High elevation
2xl Full overlays Maximum depth

The Process

  1. Get base color: Shadow color (default: black with opacity)
  2. Ask style:
    • Soft - Large blur, low opacity (modern, subtle)
    • Sharp - Small blur, higher opacity (defined edges)
    • Layered - Multiple shadows per level (most realistic)
  3. Ask levels: How many elevation steps (5-7 typical)
  4. Ask dark mode: Generate inverted/adjusted dark mode variants?
  5. Ask format: CSS, Tailwind, or JSON?
  6. Generate: Create scale with progressive blur/spread/opacity

Shadow Styles

Style Character Best For
Soft Diffuse, gentle Modern UI, cards, light themes
Sharp Defined, crisp Buttons, data-dense UI
Layered Realistic, nuanced Premium feel, modals

Layered shadows use 2-3 shadow layers per level:

  • Ambient layer: Large blur, low opacity (environmental light)
  • Key layer: Medium blur, medium opacity (directional light)
  • Edge layer: Minimal blur, subtle (contact shadow)

Output Formats

CSS Custom Properties (Layered):

:root {
  --shadow-none: none;
  --shadow-xs:
    0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-sm:
    0 1px 3px 0 rgb(0 0 0 / 0.1),
    0 1px 2px -1px rgb(0 0 0 / 0.1);
  --shadow-md:
    0 4px 6px -1px rgb(0 0 0 / 0.1),
    0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg:
    0 10px 15px -3px rgb(0 0 0 / 0.1),
    0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl:
    0 20px 25px -5px rgb(0 0 0 / 0.1),
    0 8px 10px -6px rgb(0 0 0 / 0.1);
  --shadow-2xl:
    0 25px 50px -12px rgb(0 0 0 / 0.25);
}

Tailwind Config:

module.exports = {
  theme: {
    boxShadow: {
      'none': 'none',
      'xs': '0 1px 2px 0 rgb(0 0 0 / 0.05)',
      'sm': '0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1)',
      'md': '0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1)',
      'lg': '0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1)',
      'xl': '0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1)',
      '2xl': '0 25px 50px -12px rgb(0 0 0 / 0.25)',
    }
  }
}

JSON Tokens:

{
  "shadow": {
    "none": { "value": "none" },
    "xs": { "value": "0 1px 2px 0 rgb(0 0 0 / 0.05)" },
    "sm": { "value": "0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1)" },
    "md": { "value": "0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1)" },
    "lg": { "value": "0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1)" }
  }
}

Algorithm Details

Progression factors (each level multiplies previous):

  • Y-offset: ~2x per level
  • Blur radius: ~1.5-2x per level
  • Spread: Slightly negative (prevents harsh edges)
  • Opacity: Increases slightly at higher levels

Layered shadow formula:

Level N:
  Ambient: 0 (N*4)px (N*6)px 0 rgb(0 0 0 / 0.04)
  Key:     0 (N*2)px (N*3)px -(N)px rgb(0 0 0 / 0.08)

Dark Mode Considerations

Shadows are less visible on dark backgrounds. Options:

Approach How When
Reduce opacity Cut opacity 30-50% Subtle dark UI
Add glow Light color, outward spread Neon/modern aesthetic
Ring highlight Subtle light border + shadow Card separation
Invert direction Top-lit shadows Unique style

Dark mode CSS example:

:root.dark {
  --shadow-md:
    0 4px 6px -1px rgb(0 0 0 / 0.3),
    0 0 0 1px rgb(255 255 255 / 0.05);
}

Inset Shadows

For pressed states or inner depth:

:root {
  --shadow-inner-sm: inset 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-inner-md: inset 0 2px 4px 0 rgb(0 0 0 / 0.1);
}