115 on, .browserContainer layout is flex / column,
     * and without this trick the .browserStack's resize observer
     * doesn't get notified on horizontal shrinking.
     */
    overflow: hidden;
    background: var(--letterboxing-bgcolor);
  }

  .browserContainer:not(.responsive-mode) > .browserStack:not(.exclude-letterboxing) > browser {
    width: var(--letterboxing-width) !important;
    height: var(--letterboxing-height) !important;
  }
}

:root:not([inDOMFullscreen]) .letterboxing.letterboxing-ready .browserContainer:not(.responsive-mode) > .browserStack:not(.exclude-letterboxing) {
  place-content: start center;
}
PK