message: fix content centering
diff: */
  .PanelHeader--vkcom .PanelHeader__content {
  - display: flex;
  - align-items: center;
  - justify-content: center;
  - flex-grow: 1;
  - max-width: 100%;
  + text-align: center;
  }
  .PanelHeader--vkcom::before,
  .PanelHeader--vkcom .PanelHeader__content {
  font-family: inherit;
  }
  +
  +.PanelHeader--vkcom .PanelHeader__left,
  +.PanelHeader--vkcom .PanelHeader__right {
  + flex-basis: 0;
  + flex-shrink: 0;
  + flex-grow: 1;
  +}
  