/* Fixar o cabeçalho no topo */
.cabecalho {
  position: fixed;
  top: 0;
  width: 100%;
  z-index: 9999;
  background-color: #ffffff; /* Cor de fundo branca */
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1); /* Sombra suave */
}