Resizable Panels
Let users resize sidebars, inspectors, and work areas to fit the task.
What it adds
Drag handles between panels, with minimum and maximum sizes, keyboard control, and sizes that persist.
What your agent is told to do
5
What your agent is told to do
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1
Identify the panel boundaries worth making adjustable — usually a sidebar, a list, and a detail area. Not every divider needs a handle.
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2
Give every panel a minimum and maximum size expressed relative to the container, and clamp to them during the drag rather than after it.
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3
Make each handle focusable and operable with arrow keys, with a visible focus ring and an accessible name saying what it resizes.
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4
Persist each size against the user and the specific layout it belongs to, and validate a restored size against the current container before applying it.
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5
Do not resize on every mouse move if the panels contain expensive content. Move the handle during the drag and commit the layout on release.
Edge cases it handles
6
Edge cases it handles
6- A saved size from a wide monitor must not swallow the whole layout on a laptop — clamp restored values.
- If the layout changes in a later release, stale saved sizes must be discarded rather than applied to panels that no longer exist.
- Dragging must not select text or trigger drag-and-drop inside the panels.
- Below the responsive breakpoint, panels should collapse to a stacked or single-pane layout and the handles should disappear entirely.
- Double-clicking a handle should reset that boundary to its default, and there must be a way to reset the whole layout.
- A panel dragged to its minimum must still show something meaningful, or collapse fully with an obvious way to bring it back.
Definition of done
8
Definition of done
8- Every handle enforces a minimum and maximum size during the drag.
- Handles can be focused and moved with the keyboard, with a visible focus state.
- Sizes persist per user and are re-validated against the viewport on restore.
- The layout collapses to a single-column arrangement on small screens with no orphaned handles.
- There is a reset for an individual boundary and for the whole layout.
- Dragging never selects text or leaves the pointer capture stuck.
- The feature matches the existing design system.
- No existing functionality is broken.
Related features
Beautiful Empty States
Beautiful Empty States
Replace blank screens with useful, contextual empty states.
What it does
Every list, table, and dashboard in your app has a "nothing here yet" state. Most
apps ship a blank rectangle — and it is often the very first thing a new user sees.
An empty state should say what belongs here, why it is empty, and what to do next.
How it works
- 1 Inventory the empty cases first. List every collection view in the app and
- 2 Distinguish the three kinds of empty. They are not the same, and must not
- 3 Build one reusable empty-state component from the existing design system,
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/beautiful-empty-states
Opening Hours Display
Opening Hours Display
Say whether you are open right now and when you next open.
What it does
A live open or closed state alongside the weekly hours, with holiday closures folded in.
How it works
- 1 Lead with the current state in plain words and follow it with the next transition: open until a time, or closed until a day and time. The weekly table is supporting detail, not the headline.
- 2 Store hours as intervals against the business's own zone, and keep holiday and one-off closures as overrides that win over the regular week rather than as edits to it.
- 3 Compute the state on the server for the first render so the page does not briefly claim the wrong thing, then let the page update itself as the clock crosses a boundary without a reload.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/opening-hours-display
Dark Mode
Dark Mode
Add a dark theme that respects the system preference and the user's choice.
What it does
A complete dark theme, defaulting to the operating system preference and overridable by the user.
How it works
- 1 Audit every colour in the app first and report where they are defined. If colours are hardcoded throughout, extract them into tokens before anything else — that refactor is the bulk of this work.
- 2 Define a dark palette against those tokens. Do not simply invert the light theme.
- 3 Default to the system preference via prefers-color-scheme, and let the user override it.
Copy the prompt
No account needed
Add this feature to my app:
https://addthisfeature.com/x/dark-mode
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.