message: Panel: new way for setting bg
diff: height: 100%;
  }
  + .Panel::after {
  + position: fixed;
  + width: 100%;
  + height: 100%;
  + height: 100vh;
  + left: 0;
  + top: 0;
  + z-index: 1;
  + content: '';
  + }
  +
  .Panel--centered .Panel__in {
  display: flex;
  align-items: center;
  box-sizing: border-box;
  width: 100%;
  min-height: 100%;
  + z-index: 2;
  }
  .Panel__in-before {
  margin-top: -1px;
  }
  -.Panel--tm-gray .Panel__in {
  +.Panel--tm-gray::after {
  background-color: var(--background_page);
  }
  -.Panel--tm-white .Panel__in {
  +.Panel--tm-white::after {
  background-color: var(--background_content);
  }
  