Theme-Aware Asset Switching
Swap logos, screenshots, and illustrations so each one suits the surface it lands on.
What it adds
A single asset reference that resolves to the correct light or dark variant at render time, with its dimensions reserved.
What your agent is told to do
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What your agent is told to do
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Find every raster and vector asset that assumes a background — logos with white knockouts, product screenshots, illustrations with dark line work, diagrams, empty-state artwork — and give each one a variant per theme.
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Resolve the variant from the same source of truth the rest of the theme uses, so a single toggle switches the palette and the artwork together rather than leaving the logo a step behind.
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Reserve each asset's dimensions in the layout before it loads, so swapping variants or waiting on a download never reflows the page around it.
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Define what renders when a variant is missing: fall back to the light asset on a neutral plate rather than showing nothing, and make the gap visible in development so the missing file gets added.
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Do not switch assets with a script that runs after the page has painted. The user sees a white logo flash on a dark page, and it happens on every navigation, which is exactly the moment people notice.
Edge cases it handles
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Edge cases it handles
7- Resolving the variant on the client after first paint produces a visible flash of the wrong asset. Decide the theme before the markup is sent, or render both variants and let the stylesheet choose so nothing swaps after paint.
- An asset whose size is not reserved shifts every element below it when it loads or changes. Declare intrinsic dimensions or an aspect ratio on every themed asset.
- A missing dark variant must degrade to something readable rather than an empty frame or a broken image. A light asset on a neutral plate is acceptable; nothing at all is not.
- Server-rendered pages must produce the same variant the client would choose, or the first render will be corrected in front of the user. Where the theme is genuinely unknown at render time, use a mechanism that resolves without executing script.
- User-uploaded content has no themed variant and never will. Place it on a fixed neutral surface rather than trying to invert it.
- Printing and PDF export should use the light variants regardless of the active theme, because the output lands on white paper.
- The theme can change mid-session, from the system setting or another tab. Assets must follow that change without a reload.
Definition of done
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Definition of done
9- Every background-dependent asset has a variant for each theme, referenced through one shared mechanism.
- No asset flashes the wrong variant on load, navigation, or theme change.
- Themed assets reserve their dimensions and cause no layout shift.
- A missing variant falls back to a legible asset rather than an empty space.
- Server-rendered output matches what the client resolves, with no visible correction after hydration.
- Printed and exported output uses the light variants.
- Changing the theme mid-session updates every asset without a reload.
- 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
Motion Token System
Motion Token System
Give the app one shared vocabulary of durations and easing curves instead of ad hoc numbers.
What it does
A named set of durations and easing curves, each tied to a category of motion, replacing the timing values scattered through the app's components.
How it works
- 1 Inventory every duration and easing value currently written into the app and group them by what they do: something entering, something leaving, something being emphasised, and something changing size or position.
- 2 Name a small set of durations — roughly instant, quick, standard, and deliberate — and a small set of curves, then map each motion category to a pairing. Four or five of each is enough for an entire product.
- 3 Give entrances and exits different treatment. Something arriving should decelerate into place; something leaving should accelerate away and take less time, because nobody wants to wait for a dismissal.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/motion-token-system
Responsive Grid Tokens
Responsive Grid Tokens
Express columns, gaps, and spans as shared tokens rather than per-component guesses.
What it does
A token set describing column counts, gutters, and span behaviour at each breakpoint, used by every grid in the app.
How it works
- 1 Find the grids already in the app — card lists, dashboards, form layouts, media galleries — and record how many columns each uses at each size. The reconciled set is normally three or four column counts, not one per screen.
- 2 Define gutters from the spacing scale rather than inventing grid-specific values, so the gap between cards matches the rhythm of everything around them.
- 3 Express spans in tokens tied to the column count, so a component asking for half a row keeps working when the row drops from four columns to two instead of overflowing.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/responsive-grid-tokens
How it works
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Copy the link
Grab the Markdown instruction URL for this feature.
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Give it to your AI
Paste it into Claude Code, Cursor, v0, Lovable — whatever you build with.
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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.