How to add a css class to a Html.TextBox

<% using(Html.BeginForm()) { %>
    <div style="width:500px; padding-top:15px;">
        <span class="loginleft">
            <label for="username" class="largetext">Email:</label>&nbsp;&nbsp;
        </span>
        <span class="loginright">
            <%= Html.TextBox("email", string.Empty, new { @class = "textbox" }) %>  
        </span>
         <br />
         <br />
        <span class="loginleft">
            <label for="password" class="largetext">Password:</label>&nbsp;&nbsp;
        </span>
        <span class="loginright">
            <%= Html.Password("password", string.Empty, new { @class = "textbox" }) %>  
        </span>
        <br /> 
        <br />
        <span class="loginleft">
        &nbsp;
        </span>
        <span class="loginright">
            <%= Html.SubmitButton("loginSubmit", "Login", new { @class = "button" }) %>
        </span>
    </div>
    <% } %>