OOP implementation issue

Link of my class diagram

The idea of the project is html renderer. But i wanted to do it more dynamic by using Strategy design pattern(not sure if its strategy :D).

RenderStrategy:

public abstract class RenderStrategy
{
    private Element _RenderElement;
    public RenderStrategy(Element renderElement)
    {
        this._RenderElement = renderElement;
    }
    public abstract String Render();
}

Element:

public abstract class Element
{

    public String Render(RenderStrategy strategy)
    {
        return strategy.Render();
    }
}

my question is how should CompositeElement look like without the need of RenderCompositeElementStrategy