title: Change label color when input has .ng-invalid
body: <p>My form is built as a <strong>template driven</strong>.</p>
  
  <pre><code>&lt;div class="form-group"&gt;
  
      &lt;label for="guitar" class="col-sm-6"&gt;Guitar:&lt;/label&gt;
  
      &lt;div class="col-sm-6"&gt;
          &lt;input id="guitar" type="text"&gt;
          &lt;p *ngIf="template driven template ngIf"&gt;Warning!&lt;/p&gt;
      &lt;/div&gt;
  
  &lt;/div&gt;
  </code></pre>
  
  <p>When in <code>&lt;input id="guitar"&gt;</code> I enter invalid characters, then <code>&lt;input&gt;</code> will get the style:</p>
  
  <p><code>border: 2px solid red</code> from:</p>
  
  <pre><code>input.form-control.ng-invalid.ng-touched {
    border: 2px solid red;
  }
  </code></pre>
  
  <p>and shows <code>&lt;p&gt;Warning!&lt;/p&gt;</code>.</p>
  
  <p>It works great.</p>
  
  <p>Is it possible to change the color:</p>
  
  <pre><code>&lt;label for="guitar"&gt;Guitar:&lt;/label&gt;
  </code></pre>
  
  <p>to <strong>red</strong> when <code>&lt;p&gt;Warning!&lt;/p&gt;</code> is displayed and <code>&lt;input&gt;</code> has a <strong>border</strong>?</p>