mat-menu样式未应用于角度

我试图使用角度材料和flex css在角度2中创建一个简单的布局 .

以下是我的代码......

<div  class="background" >

<mat-toolbar fxLayout="row"   fxLayoutAlign="space-between  none" >

<div  fxLayout="column" > 
<p>SPACE STUDY</p>
<h6>Rockefeller FY 2018</h6>

<div  fxShow="true" fxHide.gt-sm="true" fxLayout="column" fxLayoutAlign="start none">

 <h6 [matMenuTriggerFor]="dashboarditems">
  <mat-icon style="transform: scale(1.2);">line_weight</mat-icon> </h6>

  <mat-menu  class="mat-menu-panel"  [overlapTrigger]="true" #dashboarditems="matMenu">


<a  routerLink='/home' routerLinkActive='active'>
<span matTooltip="HOME"><mat-icon style="color:lightgreen;">home</mat-icon></span></a>




<a >
<span matTooltip="SPACE SURVEY"><mat-icon style="color:deeppink;">explore</mat-icon></span></a>




<a  >
<span matTooltip="SPACE ADMIN"><mat-icon style="color:lightblue;">account_circle</mat-icon></span></a>




<a >
<span matTooltip="REPORTS"><mat-icon style="color: orange;">assignment</mat-icon></span></a>




<a >
<span matTooltip="JOINT USE"><mat-icon style="color:yellow;">supervisor_account</mat-icon></span></a>




<a  >
<span matTooltip="HELP"><mat-icon style="color:red;">help</mat-icon></span></a>



  </mat-menu>
</div>


</div>

<div fxLayout="row"  fxShow="true" fxHide.lt-md="true" >
<button mat-raised-button routerLink='/home' routerLinkActive='active'>
<span matTooltip="HOME"><mat-icon style="color:lightgreen;">home</mat-icon></span></button>

<button mat-raised-button >
<span matTooltip="SPACE SURVEY"><mat-icon style="color:deeppink;">explore</mat-icon></span></button>

<button mat-raised-button >
<span matTooltip="SPACE ADMIN"><mat-icon style="color:lightblue;">account_circle</mat-icon></span></button>

<button mat-raised-button >
<span matTooltip="REPORTS"><mat-icon style="color: orange;">assignment</mat-icon></span></button>

<button mat-raised-button  >
<span matTooltip="JOINT USE"><mat-icon style="color:yellow;">supervisor_account</mat-icon></span></button>

<button mat-raised-button >
<span matTooltip="HELP"><mat-icon style="color:red;">help</mat-icon></span></button>
</div>

</mat-toolbar>

</div>


<style>

.background {
/* Remember to use the other versions for IE 10 and older browsers! */
display: flex;
min-height: 100%;
font-family: 'verdana', sans-serif;
color: #fff;
height:100vh;
background: #222222;
background: #16222A; /* fallback for old browsers */
background: -webkit-linear-gradient(to top, #16222A , #3A6073); /* Chrome 10-25, Safari 5.1-6 */
background: linear-gradient(to top, #16222A , #3A6073); /* W3C, IE 10+/ Edge, Firefox 16+, Chrome 26+, Opera 12+, Safari 7+ */
}

p{
font-size:20px;
font-weight:bold;
font-family: 'verdana', sans-serif;
margin:3px;
}

h6{
    font-size:12px;
    font-weight:bold;
    font-family: 'verdana', sans-serif;
}

.mat-raised-button{
    text-align:left;
    border-radius:10px;
    font-size:11px;
    font-weight:bold;
    font-family: 'verdana', sans-serif;
    color:white;
    background:transparent;
}

.mat-icon {
    transform: scale(1.5);
}

.matTooltip{
    font-size:11px;
    font-weight:bold;
    font-family: 'verdana', sans-serif;
    }

.mat-menu-panel {
    min-width: 35px;
    max-width: 280px;
    overflow: auto;
    -webkit-overflow-scrolling: touch;
    max-height: calc(100vh - 48px);
    border-radius: 2px;
    outline: 0;
    background: transparent;
    padding-left: 10px;
}
</style>

这是我的输出

在这里，我试图将mat-menu容器的背景颜色更改为透明，并设置其他一些样式 .

当我在控制台中更改时，它会被反射回来，如下所示

但是，当我在代码中应用相同的更改时，样式未应用 .

我还尝试在组件和我添加mat菜单的div中明确添加class =“mat-menu-panel” .

但仍然没有应用样式..

任何人都可以帮我修理这个样式..

请在这里访问我的示例代码.. https://stackblitz.com/edit/angular-mat-formfield-flex-layout-vc3fsj?file=app%2Fapp.component.html