Hi @Wanderson,

Thank you for report the bug.

If you want to change vertical property, please change the first line in HTML code for like this:

<mdb-stepper #stepper [linear]="true" [vertical]="vertical" (window:resize)="onResize($event)" (window:load)="onResize($event)">

And then we need to make vertical variable and onResize function.

vertical = false;
onResize(event: any) {
  if (event.target.innerWidth >= 786) {
    this.vertical = false;
  } else {
    this.vertical = true;
  }
}

So, now component has a breakpoint in 786px.

Also, we will change the documentation of this component.

Thanks again, and I hope my solution will be exactly what do you need.

Best, Konrad.