*{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

.banner{
  width: 100%;
  position: absolute;
  top: 0;
  z-index: -1000;

}
.img_banner{
  width: 100%;
  max-height: 100vh;
}
#carreras{
  width: 80%;
  margin: auto;
  height: 500px;
  background-color: cyan;
  margin-top: 80vh;
}