聚合物纸 - 标题 - 面板未在纸抽屉面板中显示任何内容

:host {
    display:block;
}

.paper-header {
    height: 60px;
    font-size: 20px;
    color: var(--text-primary-color);
    line-height: 60px;
    padding: 0 30px;
}

.blue .paper-header {
    background-color: var(--default-primary-color);
}

.list-panel {
    background-color: #fafafa;
    
    --paper-header-panel-standard-container: {
        border-right: 1px solid #ccc;
    };
}

paper-toolbar {
    background-color: #42A5F5;
}

.list {
    background-color: #FFFFFF;
}

.list  paper-item {
    height: 80px;
    border-bottom: 1px solid #dedede;
    background-color: #fafafa;
    color: #000000;
}

.main-drawer-panel:not([narrow]) [list-toggle] {
    display: none;
}

.content {
    height: 3000px;
}