How can I make the pseudo-class appear to the left instead of to the right in the MatExpansionModule component of angular material?

I am using this component of angular material:

https://material.angular.io/components/expansion/overview

I would like align the seudoclass to the left instead to the right.

 <mat-expansion-panel>
  <mat-expansion-panel-header>
    <mat-panel-title>
      This is the expansion title
    </mat-panel-title>
    <mat-panel-description>
      This is a summary of the content
    </mat-panel-description>
  </mat-expansion-panel-header>

  <p>This is the primary content of the panel.</p>

</mat-expansion-panel>

move the seudoclass here

How can I make the pseudo-class appear to the left instead of to the right ?

Thanks,