/* Reset y básicos */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body, html {
  width: 100%;
  height: 100%;
  font-family: 'Helvetica', sans-serif;
  overflow-x: hidden;
}

/* --- Pantalla de sobre inicial --- */
#envelope {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: #fff;
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 999;
}

#envelope img {
  position: absolute;
  max-width: 80%;
  max-height: 80%;
  transition: transform 1s ease, opacity 1s ease;
  cursor: pointer;
}

#envelope-back {
  z-index: 1;
}

#envelope-front {
  z-index: 2;
}

/* Animación de apertura */
.open-front {
  transform: rotateX(180deg) translateY(-50px);
  opacity: 0;
}

.open-back {
  transform: translateY(-100vh);
  opacity: 0;
}

/* Contenedor principal oculto al inicio */
.hidden {
  display: none;
}

/* --- Secciones --- */
section {
  min-height: 100vh;
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  padding: 2rem;
  scroll-behavior: smooth;
}

.full-img {
  width: 90%;
  max-width: 800px;
  height: auto;
  border-radius: 10px;
  box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

/* Sticky titles */
.sticky-title {
  position: sticky;
  top: 0;
  background: rgba(255,255,255,0.9);
  width: 100%;
  text-align: center;
  padding: 1rem 0;
  font-size: 2rem;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
  z-index: 10;
}

/* Video container con marco */
.video-container {
  position: relative;
  width: 90%;
  max-width: 800px;
  margin: 2rem 0;
}

.video-container video {
  width: 100%;
  border-radius: 10px;
  display: block;
}

.video-frame {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

/* Información y FAQ */
.info-text, .faq p {
  margin-top: 1rem;
  font-size: 1.2rem;
  max-width: 800px;
  text-align: center;
  line-height: 1.5;
}

/* Responsive */
@media (max-width: 768px) {
  .sticky-title {
    font-size: 1.5rem;
  }

  .info-text, .faq p {
    font-size: 1rem;
    padding: 0 1rem;
  }

  .video-container {
    width: 100%;
  }

  .full-img {
    width: 100%;
  }
}