The Layout plugin manages CSS transitions during layout changes and signals when the app has finished loading.

##### Behavior

The Layout plugin performs two key tasks automatically:

1. **Hold Transitions** - During window resize, CSS transitions on the sidebar, navbar, and content area are temporarily disabled to prevent visual glitches. The `hold-transition` class is added to `<body>` for the duration.

2. **App Loaded Signal** - After a 400ms delay on DOMContentLoaded, the `app-loaded` class is added to `<body>`. Use this class in CSS to defer animations until the app is ready, preventing flicker on initial page load.

##### CSS Classes

| Class | Description |
|-------|-------------|
| `hold-transition` | Temporarily disables CSS transitions on layout elements. Applied during window resize. |
| `app-loaded` | Added to `<body>` after the initial layout is ready. Use for entrance animations. |

##### Usage in CSS

```css
/* Hide sidebar transitions until the app is loaded */
body:not(.app-loaded) .app-sidebar {
  transition: none !important;
}

/* Only animate after app is loaded */
body.app-loaded .app-sidebar {
  transition: width 0.3s ease;
}
```

##### Programmatic API

The Layout plugin self-initializes on `DOMContentLoaded` — there's nothing to wire up manually. The only public method is exposed for advanced cases where you want to suppress transitions around your own DOM mutations:

```js
import { Layout } from "admin-lte"

const layout = new Layout(document.body)
layout.holdTransition(200)   // disable transitions for 200ms

// ... do something that would otherwise animate awkwardly
document.body.classList.toggle("sidebar-mini")
```

###### Methods

| Method | Returns | Description |
|---|---|---|
| `holdTransition(time?)` | `void` | Adds `hold-transition` to `<body>`, removes it after `time` milliseconds (default `100`). Use to suppress CSS transitions during programmatic layout changes. |

##### Notes

- The `hold-transition` class is automatically removed after the timeout. You don't need to clean up.
- No data attributes — the plugin reads no config and initialises with the body element on page load.
- If you need to detect when the initial page-load animations are done, watch for the `app-loaded` class on `<body>` or listen for the standard `load` event.