keep.google.com - autohide toolbar by upsiflu

/* ==UserStyle==
@name         keep.google.com - autohide toolbar
@version      20220627.20.53
@namespace    userstyles.world/user/upsiflu
@description  When you use Google Keep via keep.google.com on a desktop browser, it shows a very annoying animation each time you type (a rotating arrow). This style makes the whole toolbar transparent while the mouse cursor is away from it.
@author       upsiflu
@license      No License
==/UserStyle== */

@-moz-document domain("keep.google.com") {
header > div:not(:hover) >div:not(:first-child) {opacity:0;}
header > div>div {transition:opacity .2s;}
}