The CSS tag is useful to define a css stylesheet in the javascript file:
```js
class MyComponent extends Component {
static template = xml`
<div class="my-component">some template</div>
`;
static style = css`
.my-component {
color: red;
}
`;
}
```
The `css` tag registers internally the css information. Then, whenever the first instance of the component is created, will add a <style> tag to the document <head>.
Original commit in Owl v1: 953778dc5
We reintroduce the possibility to mount the app in first position in
a target. The option "self" has been dropped since it is now possible
for a component to have several top level nodes.
Previously, when a component node had been created and destroyed, and
the corresponding component was then recreated, the destroyed node was
reused. This commit fixes that
Bruno Boi