#chat-tab-btn {
    position: fixed;
    top: 50%;
    right: 0;
    transform: translateY(-50%);
    display: flex;
    align-items: center;
    gap: 8px;
    background: #111;
    color: #fff;
    border: none;
    padding: 12px 18px 12px 14px;
    border-radius: 10px 0 0 10px;
    cursor: pointer;
    box-shadow: -2px 2px 10px rgba(0,0,0,0.2);
    z-index: 9998;
    font-family: sans-serif;
    font-size: 14px;
    transition: padding-right 0.15s ease;
  }
  #chat-tab-btn:hover {
    padding-right: 24px;
  }
  #chat-tab-btn svg {
    flex-shrink: 0;
  }

  #chat-panel-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.35);
    z-index: 9999;
    align-items: center;
    justify-content: center;
    padding: 20px;
  }
  #chat-panel-overlay.open {
    display: flex;
  }

#chat-panel-box {
  width: 380px;
  max-width: 100%;
  height: auto;
  background: #fff;
  border-radius: 14px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  box-shadow:
    0 0 25px rgba(255,255,255,0.4),
    0 10px 40px rgba(0,0,0,0.4);
}

  #chat-panel-header {
    background: #111;
    color: #fff;
    padding: 14px 16px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    font-family: sans-serif;
    font-size: 15px;
    flex-shrink: 0;
  }
  #chat-panel-close {
    background: none;
    border: none;
    color: #fff;
    font-size: 18px;
    cursor: pointer;
    line-height: 1;
    padding: 4px;
  }

  #chat-panel-body {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 14px;
    padding: 32px;
    text-align: center;
    font-family: sans-serif;
  }
  #chat-panel-body p {
    margin: 0;
    color: #444;
    font-size: 15px;
    max-width: 320px;
  }
  #chat-panel-open-link {
    background: #111;
    color: #fff;
    text-decoration: none;
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 15px;
    font-weight: 600;
  }
  #chat-panel-open-link:hover {
    opacity: 0.9;
  }

  /* Pantallas pequeñas: tarjeta compacta centrada, con margen lateral */
  @media (max-width: 640px) {
    #chat-panel-overlay {
      padding: 16px;
    }
    #chat-panel-box {
      width: 100%;
      max-width: 360px;
      border-radius: 14px;
    }
    #chat-tab-btn span {
      display: none; /* solo el icono en móvil, para no ocupar tanto */
    }
    #chat-tab-btn {
      padding: 12px;
      border-radius: 10px 0 0 10px;
    }
  }