browser app for i3wm example

todoist.desktop

[Desktop Entry]
Version=1.0
Name=Todoist
Exec=firefox --class Todoist -P Todoist --no-remote https://todoist.com/app/#start
Terminal=false
Type=Application
Icon=~/.local/share/icons/hicolor/32x32/apps/todoist.svg

userChrome.css

/*
 *  * Do not remove the @namespace line -- it's required for correct functioning
 *   */
@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* set default namespace to XUL */

#navigator-toolbox {visibility: collapse;}
browser {margin-right: -14px; margin-bottom: -14px;}

#tabbrowser-tabs {
  visibility: collapse !important;
}

#titlebar {
  visibility: collapse;
}

tab { display: none !important; }

#sidebar-header {
  visibility: collapse !important;
}