# Tabs with a glowing indicator

> A short bar of light sits under the selected tab and glides over, halo included, when you switch.

- Category: [Filters](https://library.aimran.es/components/filters)
- Built with: HTML + CSS
- Live editor: https://library.aimran.es/blocks/uv-f-tabs-glow
- Library: AIMRAN Library (https://library.aimran.es), free, no sign-up, by Aimran Oukham

## Where to use it

Made for dark interfaces. The top navigation of a music streaming app, with Home, Explore, Saved and Profile, or the menu of a gaming community. The glow gives the active tab a neon feel, as if it were lit from below. If you were after glowing tabs or a neon navigation bar in CSS, start here.

On a white background the halo washes out, so keep it for dark themes. One bright accent colour is enough; cyan, lime or hot pink all work. Leave some space under the tabs so the light has room to spread.

## Code

### HTML

```html
<div class="uv-ftg"><button>Home</button><button class="on">Explore</button><button>Saved</button><button>Profile</button><span class="g"></span></div>
```

### CSS

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

.uv-ftg {
  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: inline-flex;
  gap: .2em;
  padding: .4em .4em 1.1em;
  border-radius: 1em;
}

.uv-ftg button {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  font-weight: 550;
  line-height: 1;
  padding: .72em 1.25em;
  border: 0;
  border-radius: 999px;
  cursor: pointer;
  background: transparent;
  color: var(--fg);
  position: relative;
  transition: color calc(0.32s / var(--k)) cubic-bezier(.25,.1,.25,1),transform calc(0.32s / var(--k)) cubic-bezier(.34,1.56,.64,1);
  color: color-mix(in srgb,var(--fg) 55%,transparent);
  font-weight: 600;
}

.uv-ftg button:hover {
  color: var(--fg);
}

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

.uv-ftg .g {
  position: absolute;
  bottom: .55em;
  left: 0;
  height: 3px;
  border-radius: 999px;
  background: var(--c1);
  box-shadow: 0 0 6px var(--c1),0 0 18px var(--c1),0 0 34px color-mix(in srgb,var(--c1) 70%,transparent);
  transition: transform calc(0.45s / var(--k)) cubic-bezier(.34,1.56,.64,1),width calc(0.45s / var(--k)) cubic-bezier(.34,1.56,.64,1);
}
```

### JavaScript

```js
document.querySelectorAll(".uv-ftg").forEach(el => {
  const g=el.querySelector(".g"),bs=[...el.querySelectorAll("button")];const mv=b=>{g.style.width=b.offsetWidth*.55+"px";g.style.transform="translateX("+(b.offsetLeft+b.offsetWidth*.225)+"px)"};bs.forEach(b=>b.addEventListener("click",()=>{bs.forEach(x=>x.classList.remove("on"));b.classList.add("on");mv(b)}));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-ftg {
  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: inline-flex;
  gap: .2em;
  padding: .4em .4em 1.1em;
  border-radius: 1em;
}

.uv-ftg button {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  font-weight: 550;
  line-height: 1;
  padding: .72em 1.25em;
  border: 0;
  border-radius: 999px;
  cursor: pointer;
  background: transparent;
  color: var(--fg);
  position: relative;
  transition: color calc(0.32s / var(--k)) cubic-bezier(.25,.1,.25,1),transform calc(0.32s / var(--k)) cubic-bezier(.34,1.56,.64,1);
  color: color-mix(in srgb,var(--fg) 55%,transparent);
  font-weight: 600;
}

.uv-ftg button:hover {
  color: var(--fg);
}

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

.uv-ftg .g {
  position: absolute;
  bottom: .55em;
  left: 0;
  height: 3px;
  border-radius: 999px;
  background: var(--c1);
  box-shadow: 0 0 6px var(--c1),0 0 18px var(--c1),0 0 34px color-mix(in srgb,var(--c1) 70%,transparent);
  transition: transform calc(0.45s / var(--k)) cubic-bezier(.34,1.56,.64,1),width calc(0.45s / var(--k)) cubic-bezier(.34,1.56,.64,1);
}
`;

// 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 g=el.querySelector(".g"),bs=[...el.querySelectorAll("button")];const mv=b=>{g.style.width=b.offsetWidth*.55+"px";g.style.transform="translateX("+(b.offsetLeft+b.offsetWidth*.225)+"px)"};bs.forEach(b=>b.addEventListener("click",()=>{bs.forEach(x=>x.classList.remove("on"));b.classList.add("on");mv(b)}));requestAnimationFrame(()=>mv(el.querySelector("button.on")))
}

export default function FTabsGlow() {
  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-ftg"><button>Home</button><button className="on">Explore</button><button>Saved</button><button>Profile</button><span className="g"></span></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 “Tabs with a glowing indicator” block (Filters) from AIMRAN Library to my project.

## What it is
A short bar of light sits under the selected tab and glides over, halo included, when you switch.

## 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-ftg {
  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: inline-flex;
  gap: .2em;
  padding: .4em .4em 1.1em;
  border-radius: 1em;
}

.uv-ftg button {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  font-weight: 550;
  line-height: 1;
  padding: .72em 1.25em;
  border: 0;
  border-radius: 999px;
  cursor: pointer;
  background: transparent;
  color: var(--fg);
  position: relative;
  transition: color calc(0.32s / var(--k)) cubic-bezier(.25,.1,.25,1),transform calc(0.32s / var(--k)) cubic-bezier(.34,1.56,.64,1);
  color: color-mix(in srgb,var(--fg) 55%,transparent);
  font-weight: 600;
}

.uv-ftg button:hover {
  color: var(--fg);
}

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

.uv-ftg .g {
  position: absolute;
  bottom: .55em;
  left: 0;
  height: 3px;
  border-radius: 999px;
  background: var(--c1);
  box-shadow: 0 0 6px var(--c1),0 0 18px var(--c1),0 0 34px color-mix(in srgb,var(--c1) 70%,transparent);
  transition: transform calc(0.45s / var(--k)) cubic-bezier(.34,1.56,.64,1),width calc(0.45s / var(--k)) cubic-bezier(.34,1.56,.64,1);
}
`;

// 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 g=el.querySelector(".g"),bs=[...el.querySelectorAll("button")];const mv=b=>{g.style.width=b.offsetWidth*.55+"px";g.style.transform="translateX("+(b.offsetLeft+b.offsetWidth*.225)+"px)"};bs.forEach(b=>b.addEventListener("click",()=>{bs.forEach(x=>x.classList.remove("on"));b.classList.add("on");mv(b)}));requestAnimationFrame(()=>mv(el.querySelector("button.on")))
}

export default function FTabsGlow() {
  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-ftg"><button>Home</button><button className="on">Explore</button><button>Saved</button><button>Profile</button><span className="g"></span></div>
      </div>
    </>
  );
}
```

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