如何将的matMenuTriggerFor区域更改为仅在箭头上方触发

<button mat-icon-button [matMenuTriggerFor]="menu">
  <mat-icon>more_vert</mat-icon>
</button>
<mat-menu #menu="matMenu" class="custom-menu">
  <button mat-menu-item>Item 1</button>
  <button mat-menu-item>Item 2</button>
  <button mat-menu-item>Item 3</button>
</mat-menu>

.custom-menu.mat-menu-panel {
  position: absolute;
  top: -24px; /* 负值用于将菜单移到箭头上方 */
}