header {
  background: linear-gradient(#000000, #fefefe);
  margin: 0;
  width: auto;
}

.caixa {
  align-content: center;
  width: auto;
}

.img_titulo {
  align-items: center;
  align-content: center;
  width: 100vw;
}

.frist {
  background: rgb(197, 133, 4);
  justify-content: center;
  width: 100vw;
}
.img_frist {
  justify-content: center;
  align-items: center;
  align-content: center;
  width: 100vw;
}

@media screen and (max-width: 768px) {
  header {
    width: auto;
  }
}