# Engine start button

> A car start button with an aluminium bezel: the light ring fills up on start and the button shakes like an engine.

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

## Where to use it

Push-button ignition is a small ritual in modern cars, and this toggle recreates it: a brushed aluminium bezel, a glossy black cap with the label and a thin LED ring around it. On start the ring sweeps all the way round, the cap rumbles for a moment and a soft glow keeps breathing while it is on. It suits car brands, smart home and power toggles.

The main color is the light ring, red by default, and the secondary color tints the metal, from cool silver to warm titanium. The state is exposed with aria-pressed, so assistive tech knows whether the engine is running.

## Code

### HTML

```html
<button class="uvq01-eng" type="button" aria-label="Start" aria-pressed="false"><span class="led" aria-hidden="true"></span><span class="cap" aria-hidden="true"><span class="sm">Engine</span><span class="w"><span class="a">Start</span><span class="b">Turn off</span></span><span class="sm">Start · Stop</span></span></button>
```

### CSS

```css
.uvq01-eng {
  --c1: #ff3b2f;
  --c2: #c9d0d8;
  --s: 16px;
  /* tamaño */
  --k: 1;
  /* velocidad */
  --fg: #1d1d1f;
  /* texto */
  --bg: #f5f5f7;
  /* fondo */
}

@property --uvq01-ea {
  syntax: "<angle>";
  inherits: false;
  initial-value: 0deg;
}

.uvq01-eng {
  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;
  font: inherit;
  color: inherit;
  border: 0;
  margin: 0;
  background: none;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  position: relative;
  display: grid;
  place-items: center;
  width: 7.4em;
  height: 7.4em;
  border-radius: 50%;
  background: repeating-radial-gradient(circle,rgba(255,255,255,.14) 0 1px,transparent 1px 3px),conic-gradient(from 20deg,var(--c2),#7d848e,#f2f4f7,#7d848e,var(--c2),#6f7680,#eef1f4,#7d848e,var(--c2));
  box-shadow: inset 0 1px 1px #fff,0 0 0 1px #5b616a,0 .5em 1.2em -.3em rgba(0,0,0,.55);
}

.uvq01-eng::after {
  content: "";
  position: absolute;
  inset: .5em;
  border-radius: 50%;
  box-shadow: 0 0 1em .1em var(--c1),inset 0 0 .8em .1em var(--c1);
  opacity: 0;
  transition: opacity calc(0.6s / var(--k)) cubic-bezier(.25,.1,.25,1);
  pointer-events: none;
}

.uvq01-eng .led {
  position: absolute;
  inset: .52em;
  border-radius: 50%;
  background: conic-gradient(var(--c1) var(--uvq01-ea),color-mix(in srgb,var(--c1) 16%,#16161a) 0);
  -webkit-mask: radial-gradient(closest-side,#0000 calc(100% - .3em),#000 calc(100% - .28em));
  mask: radial-gradient(closest-side,#0000 calc(100% - .3em),#000 calc(100% - .28em));
  transition: --uvq01-ea calc(0.9s / var(--k)) cubic-bezier(.6,0,.2,1);
}

.uvq01-eng .cap {
  position: relative;
  display: grid;
  place-items: center;
  align-content: center;
  gap: .4em;
  width: 5.1em;
  height: 5.1em;
  border-radius: 50%;
  background: radial-gradient(circle at 50% 28%,#40434a,#16171b 66%);
  box-shadow: inset 0 .12em .2em rgba(255,255,255,.22),inset 0 -.2em .4em #000,0 .15em .35em rgba(0,0,0,.6);
  transition: transform calc(0.1s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uvq01-eng .sm {
  font-size: .45em;
  font-weight: 700;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: rgba(255,255,255,.5);
}

.uvq01-eng .w {
  display: grid;
  justify-items: center;
}

.uvq01-eng .a,.uvq01-eng .b {
  grid-area: 1/1;
  font-size: .68em;
  font-weight: 800;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: #f3f3f3;
  transition: color calc(0.4s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uvq01-eng .b {
  visibility: hidden;
}

.uvq01-eng[aria-pressed="true"] .a {
  visibility: hidden;
}

.uvq01-eng[aria-pressed="true"] .b {
  visibility: visible;
  color: color-mix(in srgb,var(--c1) 45%,#fff);
}

.uvq01-eng[aria-pressed="true"] .led {
  --uvq01-ea: 360deg;
}

.uvq01-eng[aria-pressed="true"]::after {
  opacity: .55;
  animation: uvq01-eng-br calc(2.4s / var(--k)) ease-in-out calc(0.9s / var(--k)) infinite;
}

.uvq01-eng[aria-pressed="true"] .cap {
  animation: uvq01-eng-rb calc(0.08s / var(--k)) linear calc(0.75s / var(--k)) 6;
}

.uvq01-eng:hover .led {
  filter: brightness(1.35);
}

.uvq01-eng:active .cap {
  transform: scale(.95);
}

.uvq01-eng:focus-visible {
  outline: 2px solid var(--c1);
  outline-offset: 3px;
}

@keyframes uvq01-eng-br {
  50% {
    opacity: .25;
  }
}

@keyframes uvq01-eng-rb {
  0%,100% {
    translate: 0 0;
  }
  25% {
    translate: .04em -.03em;
  }
  75% {
    translate: -.04em .03em;
  }
}

@media (prefers-reduced-motion:reduce) {
  .uvq01-eng,.uvq01-eng *,.uvq01-eng *::before,.uvq01-eng *::after {
    animation-duration: .01ms!important;
    animation-iteration-count: 1!important;
    transition-duration: .01ms!important;
  }
}
```

### JavaScript

```js
document.querySelectorAll(".uvq01-eng").forEach(el => {
  el.addEventListener("click",()=>el.setAttribute("aria-pressed",el.getAttribute("aria-pressed")==="true"?"false":"true"))
});
```

### 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 = `
@property --uvq01-ea {
  syntax: "<angle>";
  inherits: false;
  initial-value: 0deg;
}

.uvq01-eng {
  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;
  font: inherit;
  color: inherit;
  border: 0;
  margin: 0;
  background: none;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  position: relative;
  display: grid;
  place-items: center;
  width: 7.4em;
  height: 7.4em;
  border-radius: 50%;
  background: repeating-radial-gradient(circle,rgba(255,255,255,.14) 0 1px,transparent 1px 3px),conic-gradient(from 20deg,var(--c2),#7d848e,#f2f4f7,#7d848e,var(--c2),#6f7680,#eef1f4,#7d848e,var(--c2));
  box-shadow: inset 0 1px 1px #fff,0 0 0 1px #5b616a,0 .5em 1.2em -.3em rgba(0,0,0,.55);
}

.uvq01-eng::after {
  content: "";
  position: absolute;
  inset: .5em;
  border-radius: 50%;
  box-shadow: 0 0 1em .1em var(--c1),inset 0 0 .8em .1em var(--c1);
  opacity: 0;
  transition: opacity calc(0.6s / var(--k)) cubic-bezier(.25,.1,.25,1);
  pointer-events: none;
}

.uvq01-eng .led {
  position: absolute;
  inset: .52em;
  border-radius: 50%;
  background: conic-gradient(var(--c1) var(--uvq01-ea),color-mix(in srgb,var(--c1) 16%,#16161a) 0);
  -webkit-mask: radial-gradient(closest-side,#0000 calc(100% - .3em),#000 calc(100% - .28em));
  mask: radial-gradient(closest-side,#0000 calc(100% - .3em),#000 calc(100% - .28em));
  transition: --uvq01-ea calc(0.9s / var(--k)) cubic-bezier(.6,0,.2,1);
}

.uvq01-eng .cap {
  position: relative;
  display: grid;
  place-items: center;
  align-content: center;
  gap: .4em;
  width: 5.1em;
  height: 5.1em;
  border-radius: 50%;
  background: radial-gradient(circle at 50% 28%,#40434a,#16171b 66%);
  box-shadow: inset 0 .12em .2em rgba(255,255,255,.22),inset 0 -.2em .4em #000,0 .15em .35em rgba(0,0,0,.6);
  transition: transform calc(0.1s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uvq01-eng .sm {
  font-size: .45em;
  font-weight: 700;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: rgba(255,255,255,.5);
}

.uvq01-eng .w {
  display: grid;
  justify-items: center;
}

.uvq01-eng .a,.uvq01-eng .b {
  grid-area: 1/1;
  font-size: .68em;
  font-weight: 800;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: #f3f3f3;
  transition: color calc(0.4s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uvq01-eng .b {
  visibility: hidden;
}

.uvq01-eng[aria-pressed="true"] .a {
  visibility: hidden;
}

.uvq01-eng[aria-pressed="true"] .b {
  visibility: visible;
  color: color-mix(in srgb,var(--c1) 45%,#fff);
}

.uvq01-eng[aria-pressed="true"] .led {
  --uvq01-ea: 360deg;
}

.uvq01-eng[aria-pressed="true"]::after {
  opacity: .55;
  animation: uvq01-eng-br calc(2.4s / var(--k)) ease-in-out calc(0.9s / var(--k)) infinite;
}

.uvq01-eng[aria-pressed="true"] .cap {
  animation: uvq01-eng-rb calc(0.08s / var(--k)) linear calc(0.75s / var(--k)) 6;
}

.uvq01-eng:hover .led {
  filter: brightness(1.35);
}

.uvq01-eng:active .cap {
  transform: scale(.95);
}

.uvq01-eng:focus-visible {
  outline: 2px solid var(--c1);
  outline-offset: 3px;
}

@keyframes uvq01-eng-br {
  50% {
    opacity: .25;
  }
}

@keyframes uvq01-eng-rb {
  0%,100% {
    translate: 0 0;
  }
  25% {
    translate: .04em -.03em;
  }
  75% {
    translate: -.04em .03em;
  }
}

@media (prefers-reduced-motion:reduce) {
  .uvq01-eng,.uvq01-eng *,.uvq01-eng *::before,.uvq01-eng *::after {
    animation-duration: .01ms!important;
    animation-iteration-count: 1!important;
    transition-duration: .01ms!important;
  }
}
`;

// 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) {
  el.addEventListener("click",()=>el.setAttribute("aria-pressed",el.getAttribute("aria-pressed")==="true"?"false":"true"))
}

export default function BtnEngineStart() {
  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": "#ff3b2f",
          "--c2": "#c9d0d8",
          "--s": "16px",
          "--k": "1",
          "--fg": "#1d1d1f",
          "--bg": "#f5f5f7",
        } as CSSProperties}
      >
        <button className="uvq01-eng" type="button" aria-label="Start" aria-pressed="false"><span className="led" aria-hidden="true"></span><span className="cap" aria-hidden="true"><span className="sm">Engine</span><span className="w"><span className="a">Start</span><span className="b">Turn off</span></span><span className="sm">Start · Stop</span></span></button>
      </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 “Engine start button” block (Buttons) from AIMRAN Library to my project.

## What it is
A car start button with an aluminium bezel: the light ring fills up on start and the button shakes like an engine.

## Chosen settings
- Main color: #ff3b2f
- Secondary color: #c9d0d8
- Size: 16px (from 12 to 24px)
- Speed: 1x (from 0.5 to 2x)
- Text: "Arrancar"

## 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 = `
@property --uvq01-ea {
  syntax: "<angle>";
  inherits: false;
  initial-value: 0deg;
}

.uvq01-eng {
  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;
  font: inherit;
  color: inherit;
  border: 0;
  margin: 0;
  background: none;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  position: relative;
  display: grid;
  place-items: center;
  width: 7.4em;
  height: 7.4em;
  border-radius: 50%;
  background: repeating-radial-gradient(circle,rgba(255,255,255,.14) 0 1px,transparent 1px 3px),conic-gradient(from 20deg,var(--c2),#7d848e,#f2f4f7,#7d848e,var(--c2),#6f7680,#eef1f4,#7d848e,var(--c2));
  box-shadow: inset 0 1px 1px #fff,0 0 0 1px #5b616a,0 .5em 1.2em -.3em rgba(0,0,0,.55);
}

.uvq01-eng::after {
  content: "";
  position: absolute;
  inset: .5em;
  border-radius: 50%;
  box-shadow: 0 0 1em .1em var(--c1),inset 0 0 .8em .1em var(--c1);
  opacity: 0;
  transition: opacity calc(0.6s / var(--k)) cubic-bezier(.25,.1,.25,1);
  pointer-events: none;
}

.uvq01-eng .led {
  position: absolute;
  inset: .52em;
  border-radius: 50%;
  background: conic-gradient(var(--c1) var(--uvq01-ea),color-mix(in srgb,var(--c1) 16%,#16161a) 0);
  -webkit-mask: radial-gradient(closest-side,#0000 calc(100% - .3em),#000 calc(100% - .28em));
  mask: radial-gradient(closest-side,#0000 calc(100% - .3em),#000 calc(100% - .28em));
  transition: --uvq01-ea calc(0.9s / var(--k)) cubic-bezier(.6,0,.2,1);
}

.uvq01-eng .cap {
  position: relative;
  display: grid;
  place-items: center;
  align-content: center;
  gap: .4em;
  width: 5.1em;
  height: 5.1em;
  border-radius: 50%;
  background: radial-gradient(circle at 50% 28%,#40434a,#16171b 66%);
  box-shadow: inset 0 .12em .2em rgba(255,255,255,.22),inset 0 -.2em .4em #000,0 .15em .35em rgba(0,0,0,.6);
  transition: transform calc(0.1s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uvq01-eng .sm {
  font-size: .45em;
  font-weight: 700;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: rgba(255,255,255,.5);
}

.uvq01-eng .w {
  display: grid;
  justify-items: center;
}

.uvq01-eng .a,.uvq01-eng .b {
  grid-area: 1/1;
  font-size: .68em;
  font-weight: 800;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: #f3f3f3;
  transition: color calc(0.4s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uvq01-eng .b {
  visibility: hidden;
}

.uvq01-eng[aria-pressed="true"] .a {
  visibility: hidden;
}

.uvq01-eng[aria-pressed="true"] .b {
  visibility: visible;
  color: color-mix(in srgb,var(--c1) 45%,#fff);
}

.uvq01-eng[aria-pressed="true"] .led {
  --uvq01-ea: 360deg;
}

.uvq01-eng[aria-pressed="true"]::after {
  opacity: .55;
  animation: uvq01-eng-br calc(2.4s / var(--k)) ease-in-out calc(0.9s / var(--k)) infinite;
}

.uvq01-eng[aria-pressed="true"] .cap {
  animation: uvq01-eng-rb calc(0.08s / var(--k)) linear calc(0.75s / var(--k)) 6;
}

.uvq01-eng:hover .led {
  filter: brightness(1.35);
}

.uvq01-eng:active .cap {
  transform: scale(.95);
}

.uvq01-eng:focus-visible {
  outline: 2px solid var(--c1);
  outline-offset: 3px;
}

@keyframes uvq01-eng-br {
  50% {
    opacity: .25;
  }
}

@keyframes uvq01-eng-rb {
  0%,100% {
    translate: 0 0;
  }
  25% {
    translate: .04em -.03em;
  }
  75% {
    translate: -.04em .03em;
  }
}

@media (prefers-reduced-motion:reduce) {
  .uvq01-eng,.uvq01-eng *,.uvq01-eng *::before,.uvq01-eng *::after {
    animation-duration: .01ms!important;
    animation-iteration-count: 1!important;
    transition-duration: .01ms!important;
  }
}
`;

// 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) {
  el.addEventListener("click",()=>el.setAttribute("aria-pressed",el.getAttribute("aria-pressed")==="true"?"false":"true"))
}

export default function BtnEngineStart() {
  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": "#ff3b2f",
          "--c2": "#c9d0d8",
          "--s": "16px",
          "--k": "1",
          "--fg": "#1d1d1f",
          "--bg": "#f5f5f7",
        } as CSSProperties}
      >
        <button className="uvq01-eng" type="button" aria-label="Start" aria-pressed="false"><span className="led" aria-hidden="true"></span><span className="cap" aria-hidden="true"><span className="sm">Engine</span><span className="w"><span className="a">Start</span><span className="b">Turn off</span></span><span className="sm">Start · Stop</span></span></button>
      </div>
    </>
  );
}
```

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