title: Facing issue in adding style to ng-container for only inside a div
body: <p>I am trying to mimic the behavior of mat-form-field for required validation on ng-select
  In order to mimic the behaviour I need to add border and color as red when mat-error trigeered.</p>
  <p>Here is my HTML</p>
  <pre><code> &lt;form (fromgroup)=&quot;form&quot;&gt;
    &lt;div id=&quot;div1&quot;&gt;
      &lt;ng-select
      formcontrolName=&quot;gender&quot;
      [(ng-model)]=names
      required
      &gt;
      &lt;ng-template let-items=&quot;$items&quot;&gt;
      &lt;input
       type=checkbox
      select All
      /&gt;
      &lt;/ng-template&gt;
      &lt;/ng-select&gt;
      &lt;mat-error class=&quot;ng-select-error ng-select-required&quot; 
      *ngif=&quot;!form.controls[&quot;gender&quot;].valid&amp;&amp; form.controls[&quot;gender&quot;].touched&quot;
      &gt;
      
      &lt;/mat-error&gt;
     &lt;/div&gt;
   &lt;/form&gt;
  </code></pre>
  <p>What Ia m trying to do is when he user touches the ng-select and did not select any item for checkbox,we should highlight the ng-select drodown with red color</p>
  <p>I tried with the css but it snot highlighting the ng-select</p>
  <p>scss:</p>
  <pre><code>.ng-select-required{
      #div1 .ng-select-container {border-bottom: solid 1px red }
      #div1 .ng-placeholder {color:red}
      #div1 .ng-arrow {color:red}
      }
   .ng-select-error{
  font-size:12px
  
  }
  </code></pre>
  <p>I am trying to do the with the above css but it is not highlighting the ng-container and ng-select .
  Please let me know why css is not working or anything I am doing wrong</p>