# Border light loader

> A streak of light that runs around the edge of a rounded square, like a tile waiting for its content.

- Category: [Loaders](https://library.aimran.es/components/loaders)
- Built with: HTML + CSS
- Live editor: https://library.aimran.es/blocks/css-border-light
- Library: AIMRAN Library (https://library.aimran.es), free, no sign-up, by Aimran Oukham

## Where to use it

This loader looks like an empty tile with light tracing its border, so it works well as a placeholder: an app icon being generated, a profile picture uploading or a product thumbnail in a shop builder. It also fits the image slot of an AI tool while the picture is rendered. Pure CSS, one element.

The inside is painted with the page background color, so make sure it matches your page, or you will see a square patch. Keep the two colors close for a soft glow, or push them apart for a sharper, more techy trace.

## Code

### HTML

```html
<div class="ul-bl"></div>
```

### CSS

```css
.ul-bl {
  --c1: #0071e3;
  --c2: #8ec5ff;
  --s: 72px;
  /* tamaño */
  --k: 1;
  /* velocidad */
  --bg: #f5f5f7;
}

.ul-bl {
  position: relative;
  width: calc(var(--s) * 1.6);
  height: calc(var(--s) * 1.6);
  border-radius: 28%;
  overflow: hidden;
  background: color-mix(in srgb,var(--c1) 12%,transparent);
}

.ul-bl::before {
  content: "";
  position: absolute;
  inset: -50%;
  background: conic-gradient(from 0deg,transparent 0 70%,var(--c2) 85%,var(--c1) 100%);
  animation: ul-spin calc(1.8s / var(--k)) linear infinite;
}

.ul-bl::after {
  content: "";
  position: absolute;
  inset: 3px;
  border-radius: calc(28% - 1px);
  background: var(--bg);
}

@keyframes ul-spin {
  to {
    transform: rotate(360deg);
  }
}
```

### React

```tsx
import type { CSSProperties } from "react";

const css = `
.ul-bl {
  position: relative;
  width: calc(var(--s) * 1.6);
  height: calc(var(--s) * 1.6);
  border-radius: 28%;
  overflow: hidden;
  background: color-mix(in srgb,var(--c1) 12%,transparent);
}

.ul-bl::before {
  content: "";
  position: absolute;
  inset: -50%;
  background: conic-gradient(from 0deg,transparent 0 70%,var(--c2) 85%,var(--c1) 100%);
  animation: ul-spin calc(1.8s / var(--k)) linear infinite;
}

.ul-bl::after {
  content: "";
  position: absolute;
  inset: 3px;
  border-radius: calc(28% - 1px);
  background: var(--bg);
}

@keyframes ul-spin {
  to {
    transform: rotate(360deg);
  }
}
`;

export default function LoaderBorderLight() {
  return (
    <>
      <style>{css}</style>
      <div
        style={{
          "--c1": "#0071e3",
          "--c2": "#8ec5ff",
          "--s": "72px",
          "--k": "1",
          "--bg": "#f5f5f7",
        } as CSSProperties}
      >
        <div className="ul-bl"></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 “Border light loader” block (Loaders) from AIMRAN Library to my project.

## What it is
A streak of light that runs around the edge of a rounded square, like a tile waiting for its content.

## Chosen settings
- Main color: #0071e3
- Secondary color: #8ec5ff
- Size: 72px (from 24 to 120px)
- 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
import type { CSSProperties } from "react";

const css = `
.ul-bl {
  position: relative;
  width: calc(var(--s) * 1.6);
  height: calc(var(--s) * 1.6);
  border-radius: 28%;
  overflow: hidden;
  background: color-mix(in srgb,var(--c1) 12%,transparent);
}

.ul-bl::before {
  content: "";
  position: absolute;
  inset: -50%;
  background: conic-gradient(from 0deg,transparent 0 70%,var(--c2) 85%,var(--c1) 100%);
  animation: ul-spin calc(1.8s / var(--k)) linear infinite;
}

.ul-bl::after {
  content: "";
  position: absolute;
  inset: 3px;
  border-radius: calc(28% - 1px);
  background: var(--bg);
}

@keyframes ul-spin {
  to {
    transform: rotate(360deg);
  }
}
`;

export default function LoaderBorderLight() {
  return (
    <>
      <style>{css}</style>
      <div
        style={{
          "--c1": "#0071e3",
          "--c2": "#8ec5ff",
          "--s": "72px",
          "--k": "1",
          "--bg": "#f5f5f7",
        } as CSSProperties}
      >
        <div className="ul-bl"></div>
      </div>
    </>
  );
}
```

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