Frontend & browser·Layout, CSS and the cascade
you hid the panel and everything below it moved up to fill the space it used to take.
display: none
Also calledhidden element
Removing an element from the render tree entirely: it takes no space, is not painted, is not reachable by keyboard, and is not announced by a screen reader. Toggling it forces a full reflow of everything after it, and any transition on the element cannot run because there is no box to transition. It is the right choice when the content genuinely should not exist for anyone, and the wrong one when you only wanted it invisible.