### Collapse

Renders a component with collapsible content.

* Use the `React.setState()` hook to create the `isCollapsed` state variable with an initial value of `props.collapsed`.
* Use an object, `style`, to hold the styles for individual components and their states.
* Use a `<div>` to wrap both the `<button>` that alters the component's `isCollapsed` state and the content of the component, passed down via `props.children`.
* Determine the appearance of the content, based on `isCollapsed` and apply the appropriate CSS rules from the `style` object.
* Finally, update the value of the `aria-expanded` attribute based on `isCollapsed` to make the component accessible.

```jsx
function Collapse(props) {
  const [isCollapsed, setIsCollapsed] = React.useState(props.collapsed);

  const style = {
    collapsed: {
      display: 'none'
    },
    expanded: {
      display: 'block'
    },
    buttonStyle: {
      display: 'block',
      width: '100%'
    }
  };

  return (
    <div>
      <button style={style.buttonStyle} onClick={() => setIsCollapsed(!isCollapsed)}>
        {isCollapsed ? 'Show' : 'Hide'} content
      </button>
      <div
        className="collapse-content"
        style={isCollapsed ? style.collapsed : style.expanded}
        aria-expanded={isCollapsed}
      >
        {props.children}
      </div>
    </div>
  );
}
```

```jsx
ReactDOM.render(
  <Collapse>
    <h1>This is a collapse</h1>
    <p>Hello world!</p>
  </Collapse>,
  document.getElementById('root')
);
```

<!-- tags: visual,children,state -->

<!-- expertise: 2 -->