Get the <a> element in the Site.Master in another content page?

I have an HTML element <a> in my Site.Master in my webforms. I designed it like this:

<li>
    <a  runat="server" id="sbHome" href="Dashboard.aspx" class="dropdown-toggle no-arrow">
        <span class="micon bi bi-house"></span><span class="mtext">Home</span>
   </a>
</li> 

I am trying to get the sbHome in my Dashboard to set it active on my code behind, like this.

 HtmlGenericControl aControl = Master.FindControl("sbHome") as HtmlGenericControl;
 if (aControl != null)
 {
    aControl.Attributes.Clear();
    aControl.Attributes.Add("class", "dropdown-toggle no-arrow active");             
 }

yet, The Master.FindControl method returns null. How can I possibly get this element from my content page?