Change placeholder color in time control's AM/PM control

I purchased the Bistro 3 website and have a Gravity Form’s date/time in one of the forms. I need to change the AM/PM placeholder color to white. I am having trouble identifying the css syntax to target that control. Here is what I have:

#gform .gfield_time_ampm ginput_container ginput_container_time
.input_2_2_3 {color:#FFFFFF;}