How to create onClick event to the icon in ASP.NET C#

kindly help me out for this issue, Onclick event for the icon is not working!

HTML :

<button id="create_project" runat="server" onclick="create_new_project" style="outline: none; border: none;"><i class='bx bxs-add'></i></button>

code behind:

protected void create_new_project(object sender, EventArgs e)
    {
        main_content.Visible = true;
        defualt_content.Visible = false;
    }

where main_content and default_content are two