更改引导程序中活动列表项的背景颜色

I have item group list

我有项目组列表

<div id="MainMenu">
    <div class="list-group panel">
        <a href="/go.html?url=#why" class="list-group-item" data-toggle="collapse" data-parent="#MainMenu">Menu 1</a>
        <div class="collapse" id="why">
            <a href="/go.html?url=" class="list-group-item" data-toggle="collapse" data-parent="#SubMenu1">Menu 1 a</a>
            <a href="/go.html?url=" class="list-group-item">Menu 1 b</a>
            <a href="/go.html?url=" class="list-group-item">Menu 1 c</a>
            <a href="/go.html?url=" class="list-group-item">Menu 1 d</a>
            <a href="/go.html?url=" class="list-group-item">Menu 1 e</a>
            <a href="/go.html?url=" class="list-group-item">Menu 1 f</a>
        </div>
        <a href="/go.html?url=#joinus" class="list-group-item" data-toggle="collapse" data-parent="#MainMenu">Menu 2</a>
        <div class="collapse" id="joinus">
            <a href="/go.html?url=" class="list-group-item">Menu 2 a</a>
            <a href="/go.html?url=" class="list-group-item">Menu 2 b</a>
            <a href="/go.html?url=" class="list-group-item">Menu 2 c</a>
            <a href="/go.html?url=" class="list-group-item">Menu 2 d</a>
            <a href="/go.html?url=" class="list-group-item">Menu 2 e</a>
        </div>
    </div>
</div>
<div id="Ma