@media (max-width: 900px) {
  .sidebar-slot { width: 80px; min-width: 80px; }
  .sidebar-header .logo span, .new-chat-btn, .search-box input { display: none; }
  .search-box { padding: 10px; display: flex; justify-content: center; }
  .chat-info, .chat-time, .unread-badge { display: none; }
  .chat-item { justify-content: center; padding: 12px 0; }
  .chat-header-actions .icon-btn:not(:last-child) { display: none; }
}

@media (max-width: 600px) {
  .nav-panel, .sidebar-slot { display: none; } /* На мобилках только чат */
  .messages-container { padding: 16px; }
  .message-row { max-width: 85%; }
}