*, *::before, *::after {
  box-sizing: border-box;
}
body {
  margin: 0;
  font-family: sans-serif;
  color: white;
}
main {
  height: 100vh;
  overflow-x: hidden;
  overflow-y: auto;
  perspective: 1.5px;
  scroll-behavior: smooth;
}
.layer {
  position: relative;
  /*height: 100vh;*/
  transform-style: preserve-3d;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 2rem;
  color: white;
}
.layer.parallax {
  height: 150vh; /* o más */
}

.layer h1 {
  font-size: 3rem;
  z-index: 1;
  transform: translateZ(0.5px) scale(0.75); /* movimiento leve hacia adelante */
}

.parallax {
  height: 150vh;
}
/* Capas de fondo */
.parallax::after {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background-size: cover;
  background-position: center;
  z-index: -1;
  transform: translateZ(-1px) scale(2); /* profundidad fuerte */
}

/* Fondo 1 */
.bg1::after {
  background-image: linear-gradient(rgba(0,0,0,0.5),rgba(0,0,0,0.5)), url('./img/3.jpg');
}
/* Fondo 2 */
.bg2::after {
  background-image: linear-gradient(rgba(0,0,0,0.5),rgba(0,0,0,0.5)), url('./img/fondo-2.jpg');
}
/* Fondo 3 */
.bg3::after {
  background-image: linear-gradient(rgba(0,0,0,0.5),rgba(0,0,0,0.5)), url('./img/fondo-3.jpg');
}

/* Secciones sin parallax */

.inicio{
  min-height: 120vh;
  background-color: #111;
}

.no-parallax {
  height: 100vh;
  background: #111;
}

/* Responsive */
@media (max-width: 768px) {
  .layer h1 {
    font-size: 2rem;
  }
}