# Jumping dot radio

> One shared dot jumps from option to option and stretches like jelly while it travels.

- Category: [Radio buttons](https://library.aimran.es/components/radios)
- Built with: HTML + CSS
- Live editor: https://library.aimran.es/blocks/uv-rd-jump
- Library: AIMRAN Library (https://library.aimran.es), free, no sign-up, by Aimran Oukham

## Where to use it

Instead of each option having its own dot, a single dot travels between them and squashes on the way. That playful motion suits quizzes and short questionnaires: the answers in a trivia game, “How many people are on your team?” during onboarding or a personality test. An animated radio group in HTML, CSS and a little JavaScript.

The stretch is the whole charm, so leave enough gap between options for the jump to be seen. It suits a vertical list of up to five or six answers; in a horizontal row it loses its effect.

## Code

### HTML

```html
<div class="uv-rdj"><span class="dt"></span><button class="on"><span class="sl"></span>One</button><button><span class="sl"></span>Two</button><button><span class="sl"></span>Three</button><button><span class="sl"></span>Four</button></div>
```

### CSS

```css
.uv-rdj {
  --c1: #0071e3;
  --c2: #8ec5ff;
  --s: 16px;
  /* tamaño */
  --k: 1;
  /* velocidad */
  --fg: #1d1d1f;
  /* texto */
  --bg: #f5f5f7;
  /* fondo */
}

.uv-rdj {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  color: var(--fg);
  -webkit-tap-highlight-color: transparent;
  position: relative;
  display: flex;
  flex-direction: column;
  gap: .85em;
  padding-left: 2em;
}

.uv-rdj button {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  display: flex;
  align-items: center;
  gap: .7em;
  font-size: var(--s);
  font-weight: 500;
  color: var(--fg);
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
  text-align: left;
  transition: color calc(0.3s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-rdj .sl {
  width: 1.25em;
  height: 1.25em;
  border-radius: 50%;
  box-shadow: inset 0 0 0 1.8px color-mix(in srgb,var(--fg) 18%,transparent);
  transition: box-shadow calc(0.3s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-rdj button.on {
  color: var(--c1);
}

.uv-rdj button.on .sl {
  box-shadow: inset 0 0 0 1.8px var(--c1);
}

.uv-rdj .dt {
  position: absolute;
  left: 2em;
  top: 0;
  width: 1.25em;
  height: 1.25em;
  border-radius: 50%;
  background: var(--c1);
  transform: translate(.31em,.31em) scale(.5);
  transition: transform calc(0.5s / var(--k)) cubic-bezier(.34,1.56,.64,1),height calc(0.35s / var(--k)) cubic-bezier(.25,.1,.25,1);
  box-shadow: 0 4px 12px color-mix(in srgb,var(--c1) 45%,transparent);
}

.uv-rdj .dt.mv {
  animation: uv-rdj calc(0.5s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

@keyframes uv-rdj {
  0% {
    scale: 1 1;
  }
  45% {
    scale: .6 1.9;
  }
  100% {
    scale: 1 1;
  }
}
```

### JavaScript

```js
document.querySelectorAll(".uv-rdj").forEach(el => {
  const dt=el.querySelector(".dt"),bs=[...el.querySelectorAll("button")];const mv=b=>{const s=b.querySelector(".sl");dt.style.transform="translate(.31em,"+(s.offsetTop+s.offsetHeight/2-dt.offsetHeight/2)+"px) scale(.5)"};bs.forEach(b=>b.addEventListener("click",()=>{bs.forEach(x=>x.classList.remove("on"));b.classList.add("on");mv(b);dt.classList.remove("mv");void dt.offsetWidth;dt.classList.add("mv")}));requestAnimationFrame(()=>mv(el.querySelector("button.on")))
});
```

### React

```tsx
// @ts-nocheck: setup() es JavaScript del DOM sin tipos, el mismo de la pestaña JS.
import { useEffect, useRef, type CSSProperties } from "react";

const css = `
.uv-rdj {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  color: var(--fg);
  -webkit-tap-highlight-color: transparent;
  position: relative;
  display: flex;
  flex-direction: column;
  gap: .85em;
  padding-left: 2em;
}

.uv-rdj button {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  display: flex;
  align-items: center;
  gap: .7em;
  font-size: var(--s);
  font-weight: 500;
  color: var(--fg);
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
  text-align: left;
  transition: color calc(0.3s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-rdj .sl {
  width: 1.25em;
  height: 1.25em;
  border-radius: 50%;
  box-shadow: inset 0 0 0 1.8px color-mix(in srgb,var(--fg) 18%,transparent);
  transition: box-shadow calc(0.3s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-rdj button.on {
  color: var(--c1);
}

.uv-rdj button.on .sl {
  box-shadow: inset 0 0 0 1.8px var(--c1);
}

.uv-rdj .dt {
  position: absolute;
  left: 2em;
  top: 0;
  width: 1.25em;
  height: 1.25em;
  border-radius: 50%;
  background: var(--c1);
  transform: translate(.31em,.31em) scale(.5);
  transition: transform calc(0.5s / var(--k)) cubic-bezier(.34,1.56,.64,1),height calc(0.35s / var(--k)) cubic-bezier(.25,.1,.25,1);
  box-shadow: 0 4px 12px color-mix(in srgb,var(--c1) 45%,transparent);
}

.uv-rdj .dt.mv {
  animation: uv-rdj calc(0.5s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

@keyframes uv-rdj {
  0% {
    scale: 1 1;
  }
  45% {
    scale: .6 1.9;
  }
  100% {
    scale: 1 1;
  }
}
`;

// Interacción en JavaScript del DOM: la misma que en la pestaña JS.
// eslint-disable-next-line @typescript-eslint/no-explicit-any
function setup(el: any) {
  const dt=el.querySelector(".dt"),bs=[...el.querySelectorAll("button")];const mv=b=>{const s=b.querySelector(".sl");dt.style.transform="translate(.31em,"+(s.offsetTop+s.offsetHeight/2-dt.offsetHeight/2)+"px) scale(.5)"};bs.forEach(b=>b.addEventListener("click",()=>{bs.forEach(x=>x.classList.remove("on"));b.classList.add("on");mv(b);dt.classList.remove("mv");void dt.offsetWidth;dt.classList.add("mv")}));requestAnimationFrame(()=>mv(el.querySelector("button.on")))
}

export default function RdJump() {
  const ref = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const el = ref.current?.firstElementChild;
    return el ? setup(el) : undefined;
  }, []);

  return (
    <>
      <style>{css}</style>
      <div
        ref={ref} style={{
          "--c1": "#0071e3",
          "--c2": "#8ec5ff",
          "--s": "16px",
          "--k": "1",
          "--fg": "#1d1d1f",
          "--bg": "#f5f5f7",
        } as CSSProperties}
      >
        <div className="uv-rdj"><span className="dt"></span><button className="on"><span className="sl"></span>One</button><button><span className="sl"></span>Two</button><button><span className="sl"></span>Three</button><button><span className="sl"></span>Four</button></div>
      </div>
    </>
  );
}
```

## Prompt for AI assistants

Paste this into ChatGPT, Claude, Cursor, v0 or Lovable to adapt the block to your stack (Tailwind, Vue, Svelte…):

````text
I want to add the “Jumping dot radio” block (Radio buttons) from AIMRAN Library to my project.

## What it is
One shared dot jumps from option to option and stretches like jelly while it travels.

## Chosen settings
- Main color: #0071e3
- Secondary color: #8ec5ff
- Size: 16px (from 12 to 24px)
- Speed: 1x (from 0.5 to 2x)

## What I need
1. Add it to my project with the same look and animation as the reference code: same sizes, colours, radii, shadows, timings and easing.
2. It is built with plain HTML and CSS (the reference wraps it in a React component with its CSS). If my project uses something else (Vue, Svelte, Astro, plain HTML…), translate it without losing any behaviour. If I use Tailwind, turn the styles into classes; if not, keep the CSS in its own file.
3. Expose the settings above as props (or CSS variables) with those values as defaults.
4. Make it work well on phones: nothing that depends only on hover, touch targets of at least 44 px and no overflow on 320 px screens.
5. Make it look right in light and dark mode.
6. Keep it accessible: semantic HTML, roles and aria-* where needed, visible focus and keyboard support.
7. Respect prefers-reduced-motion: with reduced motion, no big animations but the same end result.

## Reference code
```tsx
// @ts-nocheck: setup() es JavaScript del DOM sin tipos, el mismo de la pestaña JS.
import { useEffect, useRef, type CSSProperties } from "react";

const css = `
.uv-rdj {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  color: var(--fg);
  -webkit-tap-highlight-color: transparent;
  position: relative;
  display: flex;
  flex-direction: column;
  gap: .85em;
  padding-left: 2em;
}

.uv-rdj button {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  display: flex;
  align-items: center;
  gap: .7em;
  font-size: var(--s);
  font-weight: 500;
  color: var(--fg);
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
  text-align: left;
  transition: color calc(0.3s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-rdj .sl {
  width: 1.25em;
  height: 1.25em;
  border-radius: 50%;
  box-shadow: inset 0 0 0 1.8px color-mix(in srgb,var(--fg) 18%,transparent);
  transition: box-shadow calc(0.3s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-rdj button.on {
  color: var(--c1);
}

.uv-rdj button.on .sl {
  box-shadow: inset 0 0 0 1.8px var(--c1);
}

.uv-rdj .dt {
  position: absolute;
  left: 2em;
  top: 0;
  width: 1.25em;
  height: 1.25em;
  border-radius: 50%;
  background: var(--c1);
  transform: translate(.31em,.31em) scale(.5);
  transition: transform calc(0.5s / var(--k)) cubic-bezier(.34,1.56,.64,1),height calc(0.35s / var(--k)) cubic-bezier(.25,.1,.25,1);
  box-shadow: 0 4px 12px color-mix(in srgb,var(--c1) 45%,transparent);
}

.uv-rdj .dt.mv {
  animation: uv-rdj calc(0.5s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

@keyframes uv-rdj {
  0% {
    scale: 1 1;
  }
  45% {
    scale: .6 1.9;
  }
  100% {
    scale: 1 1;
  }
}
`;

// Interacción en JavaScript del DOM: la misma que en la pestaña JS.
// eslint-disable-next-line @typescript-eslint/no-explicit-any
function setup(el: any) {
  const dt=el.querySelector(".dt"),bs=[...el.querySelectorAll("button")];const mv=b=>{const s=b.querySelector(".sl");dt.style.transform="translate(.31em,"+(s.offsetTop+s.offsetHeight/2-dt.offsetHeight/2)+"px) scale(.5)"};bs.forEach(b=>b.addEventListener("click",()=>{bs.forEach(x=>x.classList.remove("on"));b.classList.add("on");mv(b);dt.classList.remove("mv");void dt.offsetWidth;dt.classList.add("mv")}));requestAnimationFrame(()=>mv(el.querySelector("button.on")))
}

export default function RdJump() {
  const ref = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const el = ref.current?.firstElementChild;
    return el ? setup(el) : undefined;
  }, []);

  return (
    <>
      <style>{css}</style>
      <div
        ref={ref} style={{
          "--c1": "#0071e3",
          "--c2": "#8ec5ff",
          "--s": "16px",
          "--k": "1",
          "--fg": "#1d1d1f",
          "--bg": "#f5f5f7",
        } as CSSProperties}
      >
        <div className="uv-rdj"><span className="dt"></span><button className="on"><span className="sl"></span>One</button><button><span className="sl"></span>Two</button><button><span className="sl"></span>Three</button><button><span className="sl"></span>Four</button></div>
      </div>
    </>
  );
}
```

Give me the complete final code, ready to paste, and tell me in one line where to put it in my project.
````