[Vuejs]-Opening of Modal Window pushes down rest of Elements from the main Page

I understand what was happening. I had given the same “header” name to a Div element (<div id="header">) on both the main page and the modal window, which is inserted into the main page, to which I had added some padding in the CSS of the modal window, which padding was thus added to the header in the main window (I hadn’t actually defined any CSS in the main window), explaining why my elements were shifting down.