Hi,
Thank you for the details!
I’m afraid this may not be possible. A transition will not work, as not the element below is changed, but the actual search container. The immediate pushdown is happening because the search container gets visible, and immediately takes the space inbetween the lements. While the container itself is animated by default with a “fade down drop” animation so it looks smoother, it will not affect the elements below.
I am not sure if there is any way of adding an animation to the element below only via CSS because no property chanes on it, so no transition will trigger.
The only possibility I can see is to apply an animation via javascript hooks, on the asp_resu_show and asp_results_hide events – to add customized show/hide animations to the element after the search results container.