What are the state CSS classes provided by ngModel?

In Angular, `ngModel` is a directive that provides two-way data binding for form controls. It is often used with input elements to bind the value of the input to a property in the component. However, `ngModel` itself does not provide specific CSS classes directly related to its state.

The CSS classes related to the state of form controls (like inputs) are generally associated with Angular's NgControl or NgForm directives. These classes are used to style form controls based on their validation state.

Here are some common CSS classes related to form control states in Angular:

1. **ng-valid:** Applied when the input value is valid according to the specified validation rules.

2. **ng-invalid:** Applied when the input value is invalid according to the specified validation rules.

3. **ng-pristine:** Applied when the input has not been touched by the user (pristine state).

4. **ng-dirty:** Applied when the input has been touched by the user (dirty state).

5. **ng-touched:** Applied when the input has been blurred or touched by the user.

6. **ng-untouched:** Applied when the input has not been blurred or touched by the user.

These classes are typically applied dynamically based on the state of the form control. You can use them in your styles to apply specific styling based on the validation state or user interaction with the form control.

Example:

```html
<input type="text" [(ngModel)]="myValue" name="myInput" required>

<!-- Apply styles based on control state -->
<input type="text" [(ngModel)]="myValue" name="myInput" class="my-input" [ngClass]="{'invalid-input': myInput.invalid && (myInput.dirty || myInput.touched)}">
```

In the example above, the `ng-invalid` class is applied when the input value is invalid, and the additional styling is applied conditionally using `[ngClass]` based on the control's `dirty` and `touched` states. Adjust the classes and conditions based on your specific styling requirements.