Как изменить параметры всплывающего уведомления Gnome?

.app-notification {
  padding: 10px;
  color: #BAC3CF;
  background-color: rgba(53, 57, 69, 0.95);
  background-clip: border-box;
  border-radius: 0 0 2px 2px;
  border-width: 0 1px 1px 1px;
  border-style: solid;
  border-color: rgba(31, 33, 40, 0.95); }
  .app-notification border {
    border: none; }
  .app-notification button {
    color: #BAC3CF;
    border-color: rgba(26, 28, 34, 0.35);
    background-color: rgba(102, 109, 132, 0.35); }
    .app-notification button.flat, .app-notification button.sidebar-button {
      border-color: rgba(82, 148, 226, 0); }
    .app-notification button:hover {
      color: #BAC3CF;
      border-color: rgba(26, 28, 34, 0.35);
      background-color: rgba(119, 127, 151, 0.45); }
    .app-notification button:active, .app-notification button:checked {
      color: #ffffff;
      border-color: rgba(26, 28, 34, 0.35);
      background-color: #5294e2;
      background-clip: padding-box; }
    .app-notification button:disabled {
      color: #5d626e;
      border-color: rgba(26, 28, 34, 0.35);
      background-color: rgba(102, 109, 132, 0.2); }

$cat /usr/share/themes/Adwaita/gtk-3.0/gtk.css
/* Adwaita is the default theme of GTK+ 3, this file is not used */