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
9
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
Z-Index Registry
Z-Index Registry
Keep every stacking value in one file so nobody has to guess a bigger number.
What it does
A single source of named z-index tokens, with reserved ranges per layer and a check that blocks raw values.
How it works
- 1 Find every z-index in the codebase, including inline styles and values buried in third-party overrides, and list them with the component that owns each. The count is usually higher than anyone expects and several will be arbitrary large numbers.
- 2 Reserve a range for each layer rather than assigning single values, so a new dropdown can slot between existing ones without renumbering everything above it. Leave real gaps between ranges.
- 3 Name each token after the layer it belongs to and derive the ordering from Elevation Layer Map. That feature decides what covers what; this one holds the numbers and stops them being invented locally.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/z-index-registry
Spacing Scale
Spacing Scale
Reduce the app's spacing to a small set of steps that repeat across every surface.
What it does
A named spacing scale covering gaps, padding, and section rhythm, with every existing value in the app mapped onto it.
How it works
- 1 Collect every spacing value currently in the codebase and count how often each appears. The result is usually a handful of genuine intentions surrounded by dozens of near-misses that were nudged once and never revisited.
- 2 Define a scale that is fine at the small end, where control padding lives, and coarse at the large end, where section separation lives. A linear scale gives too many indistinguishable large steps and too few small ones.
- 3 Separate the tokens used inside a component from the ones used between components and between page sections, and name them so the difference is obvious. The same number serving both purposes means a change to button padding also changes the gap between sections.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/spacing-scale
Shadow Scale
Shadow Scale
Replace ad hoc shadows with a small set tied to what each surface actually is.
What it does
A fixed ladder of shadow tokens, each named for an elevation role rather than a blur radius.
How it works
- 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.
- 2 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.
- 3 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.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/shadow-scale
How it works
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1
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.