Fluid Typography
Let type grow smoothly with the viewport instead of jumping at every breakpoint.
What it adds
Viewport-interpolated sizing for the existing type steps, bounded by a defined floor and ceiling.
What your agent is told to do
5
What your agent is told to do
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Apply interpolation to the steps already defined by Typography Scale rather than inventing new sizes. That feature owns which steps exist; this one owns how each one behaves between the narrowest and widest viewport.
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Give every fluid step an explicit minimum and maximum. An unbounded rule produces unreadable type on a small phone and absurd type on an ultrawide monitor, and both ends will be found by real users.
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Scale the display and heading steps more aggressively than body copy. Body text has a comfortable size that does not change with the window, and growing it with the viewport makes wide screens harder to read, not easier.
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Adjust line height as the size changes — large type wants proportionally tighter leading than small type — otherwise headings that looked correct on a phone become airy and loose on a desktop.
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Do not express the interpolation purely in viewport units. A size that ignores the root font size stops responding to browser zoom and to the user's own text-size preference, which is a straightforward accessibility failure.
Edge cases it handles
7
Edge cases it handles
7- Every fluid step needs a clamped floor and ceiling, since the interpolation is a straight line and will happily continue past the point of legibility in both directions.
- Sizes derived from viewport units alone do not respond to browser zoom, so the setting a low-vision user relies on stops working exactly where they need it.
- Line height must be interpolated alongside size, or the leading that suited the smallest step leaves large headings looking disconnected from themselves.
- Large display steps set for a desktop hero will overwhelm a narrow screen and wrap into four lines, so the floor for those steps needs to be much lower than their proportional value suggests.
- Interpolation driven by the viewport misbehaves inside constrained columns, sidebars, and dialogs, where the available width has nothing to do with the window width.
- Text that resizes continuously during a window drag or a device rotation causes reflow of everything below it; verify that nothing measured in a fixed pixel height sits beside fluid text.
- Values that land on fractional pixels can render inconsistently across browsers, so check the interpolated sizes at real viewport widths rather than only at the two endpoints.
Definition of done
9
Definition of done
9- Type sizes change continuously across viewport widths with no jump at a breakpoint.
- Every fluid step has an enforced minimum and maximum size.
- Type still responds correctly to browser zoom and user text-size settings.
- Line height is interpolated together with size at every step.
- Body copy scales conservatively while display steps scale more.
- Headings do not overflow or wrap awkwardly at the narrowest supported width.
- The step definitions themselves remain owned by Typography Scale.
- 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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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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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.