body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  position: relative;
}

.fondo-pantalla {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: -1;
  background: linear-gradient(to bottom right, #20a4f3, #182b3a);
}

.parte-superior {
  width: 100%;
  height: 45%;
  background-image: url("../images/backgroundb.jpg");
  background-size: cover;
  background-position: bottom;
  clip-path: polygon(0 0, 100% 0, 100% 45%, 0 100%);
}

main {
  flex-grow: 1;
  display: flex;
  justify-content: center;
  align-items: center;
}

header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 999;
  background-color: rgba(255, 255, 255, 0.25);
}

.navbar,
footer {
  background-color: rgba(255, 255, 255, 0.25);
}

footer {
  display: flex;
  justify-content: center;
}

.container {
  max-width: 600px;
  width: 100%;
}

.modal-backdrop.show {
  opacity: 0.5;
}

.modal.show .modal-dialog {
  display: flex;
  align-items: center;
  justify-content: center;
}

.modal.show .modal-dialog::before {
  content: "";
  background-color: rgba(0, 0, 0, 0.5);
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
}