<style>
.container {
border: 1.5px solid rgb(175, 175, 175);
border-radius: 10px;
margin: 10px;
padding: 5px;
}
.container-header {
align-items: center;
cursor: pointer;
display: flex;
min-height: 30px;
}
.container-name {
flex: 1;
font-size: 1rem;
}
</style>
<div class="container">
<div class="container-header" on-click="onClick_">
<div class="container-name">[[label]]</div>
<slot name="header"></slot>
<iron-icon icon="[[getArrowIcon_(expanded)]]"></iron-icon>
</div>
<template is="dom-if" if="[[expanded]]">
<slot></slot>
</template>
</div>