Untitled

const style = document.createElement('style');

style.textContent = `
  [class^='AppShell_app-shell'] {
    grid-template-columns: minmax(400px, 1fr) 10fr minmax(0px, 0fr) !important;
  }
  
  [class^='Chat_chat'] {
    display: none;
  }
`;

document.head.appendChild(style);