angular md-toast 颜色

How to show md-toast with background color

https://codepen.io/neilkalman/pen/jWBqve

<div ng-controller="AppCtrl" layout-fill="" layout="column" class="inset toastdemoBasicUsage" ng-cloak="" ng-app="MyApp">
<p>
Toast with changes to answer <a href="http://stackoverflow.com/questions/34614767/how-to-show-md-toast-with-background-color">this question on stack overflow</a>
</p>

<div layout="row" layout-sm="column" layout-align="space-around">
<md-button ng-click="showSimpleToast()">
Toast
</md-button>
</div>

</div>

<style>

　　

md-toast.md-success-toast-theme .md-toast-content {
background-color: green;
}

md-toast.md-error-toast-theme .md-toast-content {
background-color: maroon;
}

md-toast {
left: calc(50vw - 150px);
}

</style>

<script>

　　

angular.module('MyApp',['ngMaterial', 'ngMessages'])

.controller('AppCtrl', function($scope, $mdToast, $document) {

$scope.showSimpleToast = function() {
$mdToast.show(
$mdToast.simple()
.textContent('Simple lala Toast!')
.position('top')
.theme('error-toast')
.hideDelay(3000)
);
};

})

</script>