/* base: sidebar para pantallas grandes */
.chat-sidebar {
  width: 320px;            /* desktop */
  position: relative;
  transition: transform .25s ease, width .25s ease;
}

/* mobile: convertir en overlay off-canvas */
@media (max-width: 767px) {
  .chat-sidebar {
    position: fixed;
    top: 0;
    left: 0;
    height: 100vh;
    width: 80%;
    max-width: 380px;
    background: #1e1e2f;
    transform: translateX(-110%); /* off-screen */
    z-index: 1200;
    box-shadow: 0 8px 24px rgba(0,0,0,.6);
  }
  .chat-sidebar.open {
    transform: translateX(0);
  }
  /* contenido principal se pone detrás con overlay cuando sidebar abierto */
  .main-overlay {
    display: none;
  }
  .main-overlay.show {
    display: block;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.4);
    z-index: 1100;
  }
}