[css] Dynamically updating css in Angular 2

Check working Demo here

import {Component,bind} from 'angular2/core';
import {bootstrap} from 'angular2/platform/browser';
import {FORM_DIRECTIVES} from 'angular2/form';

import {Directive, ElementRef, Renderer, Input,ViewChild,AfterViewInit} from 'angular2/core';

@Component({
  selector: 'my-app',
    template: `
    <style>
       .myStyle{
        width:200px;
        height:100px;
        border:1px solid;
        margin-top:20px;
        background:gray;
        text-align:center;
       }
    </style>

          <div [class.myStyle]="my" [style.background-color]="randomColor" [style.width]="width+'px'" [style.height]="height+'px'"> my width={{width}} & height={{height}}</div>
    `,
    directives: []
})

export class AppComponent {
  my:boolean=true;
  width:number=200px;
  height:number=100px;
  randomColor;
  randomNumber;
  intervalId;
  textArray = [
    'blue',
    'green',
    'yellow',
    'orange',
    'pink'
  ];


  constructor() 
  {
    this.start();
  }

      start()
      { 
        this.randomNumber = Math.floor(Math.random()*this.textArray.length);
        this.randomColor=this.textArray[this.randomNumber];
        console.log('start' + this.randomNumber);
        this.intervalId = setInterval(()=>{
         this.width=this.width+20;
         this.height=this.height+10;
         console.log(this.width +" "+ this.height)
         if(this.width==300)
         {
           this.stop();
         }

        }, 1000);
      }
      stop()
      {
        console.log('stop');
        clearInterval(this.intervalId);
        this.width=200;
        this.height=100;
        this.start();

      }
 }

bootstrap(AppComponent, []);