Shadow Scale
Replace ad hoc shadows with a small set tied to what each surface actually is.
What it adds
A fixed ladder of shadow tokens, each named for an elevation role rather than a blur radius.
What your agent is told to do
5
What your agent is told to do
5-
1
Collect every shadow currently declared anywhere in the app and group them by what they sit on — a resting card, a hovered card, a dropdown, a dialog, a toast. Most apps have a dozen near-identical values that collapse into four or five roles.
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Name each step for its role, not its appearance. A token called menu tells the next person which surfaces may use it; a token called shadow-md-2 does not.
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Use a single light source for the whole scale, so offset, blur, and spread grow together as elevation rises. Two shadows lit from different directions on the same screen read as a rendering bug.
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Give the dark theme its own values rather than reusing the light ones. A soft black shadow on a near-black surface is invisible, so dark surfaces need a raised surface colour, a border, or both to carry the elevation.
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5
Do not let shadow be the only thing separating a surface from its background. Windows high-contrast mode, forced-colours mode, and print all strip shadows entirely, and anything relying on one alone dissolves into the page.
Edge cases it handles
7
Edge cases it handles
7- In dark themes a black shadow against a dark background conveys nothing. Elevation there has to come from a lighter surface tint or a border, with the shadow reduced to a faint halo at most.
- Any surface that uses a shadow to mark its boundary needs a fallback boundary — a background shift or a hairline border — because forced-colours mode and high-contrast settings remove shadows without warning.
- Shadows that disagree about light direction or softness look broken when they appear together. A dropdown lit from above beside a card lit from the left is immediately noticeable even to users who cannot say why.
- Print and forced-colours output should flatten the scale to nothing, or to a single hairline, rather than attempting to render a blurred shadow as a grey smear.
- Stacked elevations compound: a popover inside a dialog inside a sticky panel will render three shadows on top of each other unless nested surfaces are allowed to drop back to a flat treatment.
- Shadows on large full-width surfaces are expensive to repaint during scroll, so a sticky header with a heavy shadow will cost frames on lower-end devices.
- The elevation role a shadow claims must match the paint order it actually gets — that ordering belongs to Elevation Layer Map and Z-Index Registry, and a shadow token must never be used to fake a stacking fix.
Definition of done
8
Definition of done
8- The app has one shadow scale of no more than six steps, each named for an elevation role.
- No component declares a raw shadow value outside the scale.
- Every shadow in the scale shares a single light direction and a consistent softness progression.
- Dark theme surfaces are distinguishable from their background without relying on the shadow.
- Forced-colours mode and print render every elevated surface with a visible boundary.
- Nested elevated surfaces do not stack three or more shadows on the same visual edge.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
Semantic Color Tokens
Semantic Color Tokens
Name colours by the job they do, so changing a theme is one edit rather than a sweep.
What it does
A vocabulary of role-named colour tokens — surface, text, border, accent, danger, success — that components reference instead of literal values.
How it works
- 1 Inventory every literal colour value in the codebase and group them by the job they are doing rather than by the shade they happen to be. Two different greys used as card backgrounds are one role; the same grey used as a background and as a border is two.
- 2 Define the role names once and map each role to a value per theme. A role may resolve to a light grey in one theme and a near-black in another; what must not change is which components reference it.
- 3 Stop shared components accepting raw colour values. A primitive that takes a hex string as a prop guarantees that some product screen will hardcode a colour the themes never learn about.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/semantic-color-tokens
Container Width System
Container Width System
Give pages a few defined widths instead of a different max-width on every screen.
What it does
A small set of named page widths — narrow, standard, wide, and full-bleed — applied consistently across the app.
How it works
- 1 Measure the max-width used on every top-level page and group them. Settings forms, prose, dashboards, and data tables usually want three or four distinct widths between them, not the eleven the codebase currently has.
- 2 Pick each width from the content it holds. A reading column is bounded by comfortable line length, a settings form by field width, and a table by the number of columns that must stay visible.
- 3 Make horizontal page padding part of the container rather than something each page adds, so content never touches the viewport edge on a narrow screen even at the widest setting.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/container-width-system
Border System
Border System
Give borders defined jobs so structure, focus, and selection never look the same.
What it does
A set of border tokens covering structural dividers, interactive outlines, focus rings, selection, and error emphasis.
How it works
- 1 Audit every border in the app and sort it into one of a few jobs: separating content, outlining a control, marking focus, marking selection, or signalling an error. Anything that does not fit a job is decoration that should be removed rather than tokenised.
- 2 Keep structural borders and interactive borders visually distinct. A divider between table rows and the outline of a text input should not share a colour, or users will read inert content as clickable.
- 3 Define focus separately from selection and from hover. Focus follows the keyboard, selection follows intent, and a control that is both focused and selected must show both without one hiding the other.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/border-system
How it works
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1
Copy the link
Grab the Markdown instruction URL for this feature.
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2
Give it to your AI
Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
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3
It inspects, then implements
Your agent reads your existing app first, then adds the feature to fit it.
Works with your stack
These instructions are written to adapt. They tell the agent to detect your framework, match your existing design system, and reuse what you already have — rather than assuming a particular stack.
Need it tighter than that? Customize the feature and tell it exactly what you're running.