固定位置在Firefox中不工作

我有以下的HTML在我的网页，我想保持固定在左侧side.It侧边栏在Chrome工作正常，但Firfox不显示侧边栏固定：

I have following HTML in my webpage where I want to keep the sidebar fixed on the left side.It works fine in the Chrome but Firfox isn't displaying the sidebar as fixed :

<div id="sidebar">
    <!-- Logo -->
        <div >
            <h1>Heading</h1>
        </div>
            <!-- Nav -->
                <nav id="nav">
                    <ul>
                        <li><a href="#target1" >About</a></li>
                        <li><a href="#target2" >Works</a></li>
                        <li><a href="#target3" >Our Team</a></li>
                        <li><a href="#target4" >Contact</a></li>

                    </ul>
                </nav>

</div>

上述代码的CSS为：

the CSS for above code is :

#sidebar
{
    position: fixed;
    top: 0;
    padding: 3em 1.35em 1em 1.15em;
    height: 100%;
    width: 12em; 
    background: #364050 ;
    box-shadow: inset -0.1em 0em 0.35em 0em rgba(0,0,0,0.15);
}

请给我建议一些解决方案，使侧边栏在Firefox中保持固定。 br>

please suggest me some solution so that the sidebar will remain fixed in Firefox.

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