* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: #222;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  font-family: system-ui, -apple-system, sans-serif;
}

.app {
  width: 390px;
  height: 844px; /* Formato móvil estándar vertical */
  background: #000;
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
  box-shadow: 0 0 50px rgba(0,0,0,0.5);
}

/* PROGRESO */
.progress {
  height: 6px;
  background: rgba(255,255,255,0.2);
  z-index: 10;
}

.progress-bar {
  height: 100%;
  width: 0%;
  background: white;
  transition: width 0.3s ease;
}

/* SLIDES */
.slides {
  flex: 1;
  position: relative;
}

.slide {
  position: absolute;
  inset: 0;
  padding: 24px 20px;
  color: white;
  display: flex;
  flex-direction: column;
  justify-content: flex-start; /* texto arriba */
  text-align: center;
  transition: opacity 0.4s ease;
  overflow-y: auto;
}

.slide h1,
.slide h2,
.slide h3 {
  font-size: 2.05rem;      /* texto grande */
  line-height: 1.22;
  margin: 28px 0 14px;
}

.slide p {
  font-size: 1.05rem;
  margin-bottom: 16px;
}

.slide-counter {
  font-size: 0.9rem;
  opacity: 0.8;
  align-self: flex-end;
}

/* IMAGEN CENTRADA (una sola) */
.center-image {
  max-width: 92%;
  max-height: 55vh;
  border-radius: 16px;
  margin: 18px auto 10px; /* centrada */
  box-shadow: 0 15px 35px rgba(0,0,0,0.4);
  display: block;
  object-fit: contain;
}

/* DOBLE IMAGEN */
.double-images {
  display: flex;
  gap: 12px;
  margin-top: 18px;
  flex-wrap: wrap;
  justify-content: center;
}

.double-images img {
  flex: 1 1 48%;
  max-width: 48%;
  max-height: 40vh;
  border-radius: 14px;
  box-shadow: 0 10px 25px rgba(0,0,0,0.3);
  object-fit: cover;
  display: block;
  margin: 0 auto;
}

/* NAVEGACIÓN */
.nav {
  display: flex;
  justify-content: space-between;
  padding: 16px;
  background: rgba(0,0,0,0.2);
}

button {
  background: rgba(255,255,255,0.1);
  color: white;
  border: 1px solid rgba(255,255,255,0.2);
  padding: 10px 18px;
  border-radius: 30px;
  font-size: 0.95rem;
  cursor: pointer;
  transition: background 0.3s;
}

button:hover {
  background: rgba(255,255,255,0.2);
}

/* PORTADA */
.cover-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  text-align: center;
  height: 100%;
  padding-top: 40px;
}

.cover-image {
  width: 92%;
  border-radius: 20px;
  object-fit: cover;
  max-height: 260px;
  box-shadow: 0 15px 40px rgba(0,0,0,0.6);
  display: block;
  margin: 0 auto;
}

.cover-title {
  font-size: 2.4rem;
  margin-top: 22px;
  margin-bottom: 8px;
}

.cover-subtitle {
  font-size: 1.05rem;
  opacity: 0.9;
  margin-bottom: 24px;
}

.cover-button {
  margin-top: 12px;
  padding: 12px 28px;
  border-radius: 999px;
  font-size: 1rem;
  font-weight: 600;
  background: rgba(255,255,255,0.9);
  color: #002b36;
  border: none;
  box-shadow: 0 8px 25px rgba(0,0,0,0.35);
}

.cover-button:hover {
  background: #fff;
}

/* COMPARADOR DE IMÁGENES */
.image-slider-container {
  position: relative;
  width: 100%;
  max-width: 340px;
  height: 300px;
  border: 5px solid #fff;
  border-radius: 20px;
  overflow: hidden;
  margin: 20px auto 8px;
}

.image-slider-container .image {
  position: absolute;
  width: 100%;
  height: 100%;
  left: 0;
  top: 0;
  background-size: cover;
  background-position: center;
}

.image-slider-container .image.overlay {
  width: 50%; /* valor inicial; luego lo cambia el JS */
}

.image-slider-container .range-slider {
  position: absolute;
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
  height: 100%;
  margin: 0;
  background: #f2f2f233;
  outline: none;
  -webkit-appearance: none;
  appearance: none;
  z-index: 2;
  transition: all 200ms linear;
}

.image-slider-container .range-slider:hover {
  background: #f2f2f21a;
}

/* Thumb barra vertical */
.image-slider-container .range-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 6px;
  height: 800px;
  background: white;
  cursor: move;
  transition: all 300ms ease;
}

.image-slider-container .range-slider::-moz-range-thumb {
  width: 6px;
  height: 800px;
  background: white;
  cursor: move;
}

.slider-control {
  z-index: 3;
  position: absolute;
  display: block;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: white;
  top: 50%;
  left: 50%; /* se actualiza con JS */
  transform: translate(-60%, -50%);
  cursor: grab;
}

.slider-control::after,
.slider-control::before {
  font-family: "Font Awesome 5 Free";
  font-weight: 900;
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
}

.slider-control::after {
  content: "";
  right: 3px;
}

.slider-control::before {
  content: "";
  left: 3px;
}

.compare-labels {
  display: flex;
  justify-content: space-between;
  font-size: 0.9rem;
  margin-top: 4px;
  opacity: 0.9;
}

/* ZOOM DE IMAGEN */
.zoomable {
  cursor: zoom-in;
}

.image-modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.85);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 9999;
}

.image-modal.show {
  display: flex;
}

.image-modal img {
  max-width: 95vw;
  max-height: 90vh;
  border-radius: 12px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.7);
}

.image-modal-close {
  position: absolute;
  top: 20px;
  right: 20px;
  font-size: 2rem;
  color: #fff;
  cursor: pointer;
}

/* JUEGO DE EMPAREJAR (drag & drop) */
.matching-title {
  margin-bottom: 8px;
}

.matching-grid {
  margin-top: 8px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.matching-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.color-box {
  width: 80px;
  height: 60px;
  border-radius: 14px;
  border: 2px solid rgba(255,255,255,0.4);
}

.color-red {
  background: #8b1e3f;
}

.color-yellow {
  background: #ffcc00;
}

.color-green {
  background: #3ba56b;
}

.drop-zone {
  flex: 1;
  min-height: 60px;
  border-radius: 14px;
  border: 2px dashed rgba(255,255,255,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 6px;
}

.labels-pool {
  margin-top: 16px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.label-box {
  padding: 10px 12px;
  border-radius: 14px;
  font-size: 1rem;
  font-weight: 600;
  border: 2px solid rgba(255,255,255,0.7);
  background: rgba(0,0,0,0.25);
  cursor: grab;
  user-select: none;
}

.label-box.dragging {
  opacity: 0.7;
}

.box-linked {
  box-shadow: 0 0 15px rgba(255,255,255,0.7);
  border-color: #fff;
}

.matching-instructions {
  margin-top: 12px;
  font-size: 0.95rem;
  opacity: 0.9;
}

/* OPCIONES DE IMAGEN (image-choice) */
.image-options {
  display: flex;
  gap: 12px;
  margin-top: 10px;
  justify-content: center;
}

.image-option {
  flex: 1;
  max-width: 48%;
  border-radius: 15px;
  overflow: hidden;
  cursor: pointer;
  border: 4px solid transparent;
  transition: all 0.3s ease;
}

.image-option img {
  width: 100%;
  height: 200px;
  object-fit: cover;
  display: block;
  margin: 0 auto;
}

/* ESTILOS DE ENCUESTA (poll, por si lo usas luego) */
.poll-options {
  display: flex;
  flex-direction: column;
  gap: 15px;
  margin-top: 8px;
}

.poll-option {
  background: rgba(255,255,255,0.1);
  padding: 20px;
  border-radius: 15px;
  font-size: 1.3rem;
  font-weight: 600;
  cursor: pointer;
  border: 4px solid transparent;
  transition: all 0.3s ease;
}

/* COLORES DE SELECCIÓN PARA image-choice / poll */
.blue {
  border-color: #3498db !important;
  box-shadow: 0 0 20px rgba(52, 152, 219, 0.6);
}

.violet {
  border-color: #9b59b6 !important;
  box-shadow: 0 0 20px rgba(155, 89, 182, 0.6);
}

.yellow {
  border-color: #f1c40f !important;
  box-shadow: 0 0 20px rgba(241, 196, 15, 0.6);
  color: #f1c40f;
}

.selected-other {
  opacity: 0.3;
  transform: scale(0.95);
}