This is the 11800th most frequent Russian word.
закрытыми
"Закрытыми" means "closed" (instrumental plural form).
In this sentence, 'закрытыми' functions as an instrumental plural adjective describing the state of the windows.
Окна остались закрытыми всю ночь.
The windows remained closed all night.
Here, 'закрытыми' indicates the state of the panels within an instrumental plural construction describing the gates.
Мы проходили мимо ворот с закрытыми створками.
We passed by the gates with closed panels.
'Закрытыми' is used as part of an instrumental plural phrase describing the characteristic of the doors of the room.