/* ============================================
   LABORATORIO DE LA LUZ - ESTILOS
   ============================================ */

:root {
  --amarillo: #ffd93d;
  --naranja: #ff9f43;
  --rojo: #ff6b6b;
  --rosa: #ff8fd8;
  --morado: #a66bff;
  --azul: #4d9dff;
  --verde: #4ecb71;
  --azul-oscuro: #1b1f3b;
  --azul-noche: #0d0f24;
  --blanco: #ffffff;
  --gris-suave: #6b6f8a;
  --fondo-claro: #fef9f0;

  --fuente-principal: "Comic Sans MS", "Segoe UI", "Trebuchet MS", Verdana, sans-serif;

  --radio-grande: 24px;
  --radio-medio: 16px;
  --sombra-suave: 0 8px 24px rgba(27, 31, 59, 0.12);
  --transicion: all 0.3s ease;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--fuente-principal);
  background: var(--fondo-claro);
  color: var(--azul-oscuro);
  overflow-x: hidden;
}

img {
  max-width: 100%;
}

a {
  text-decoration: none;
  color: inherit;
}

.section-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 60px 24px;
}

.section-title {
  text-align: center;
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  margin-bottom: 8px;
}

.section-subtitle {
  text-align: center;
  color: var(--gris-suave);
  font-size: 1.1rem;
  margin-top: 0;
  margin-bottom: 40px;
}

/* ============================================
   HEADER / NAV
   ============================================ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--blanco);
  box-shadow: 0 2px 12px rgba(27, 31, 59, 0.08);
}

.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 14px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: bold;
  font-size: 1.2rem;
  color: var(--azul-oscuro);
}

.logo-icon {
  font-size: 1.6rem;
}

.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: var(--amarillo);
  border: none;
  border-radius: 10px;
  cursor: pointer;
  padding: 8px;
}

.menu-toggle .bar {
  display: block;
  height: 3px;
  width: 100%;
  background: var(--azul-oscuro);
  border-radius: 3px;
}

.main-nav {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.nav-link {
  padding: 8px 16px;
  border-radius: 999px;
  font-weight: bold;
  font-size: 0.95rem;
  background: var(--fondo-claro);
  transition: var(--transicion);
  white-space: nowrap;
}

.nav-link:hover,
.nav-link:focus-visible {
  background: var(--amarillo);
  transform: translateY(-2px);
}

/* ============================================
   HERO
   ============================================ */

.hero {
  position: relative;
  min-height: 90vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 60px 20px;
  overflow: hidden;
  background: linear-gradient(160deg, #fff6da 0%, #ffe3d1 40%, #ffd9ec 70%, #e6d9ff 100%);
  transition: background 0.8s ease;
}

.hero.is-dark {
  background: linear-gradient(160deg, var(--azul-noche) 0%, var(--azul-oscuro) 60%, #241a45 100%);
}

.hero-sparkles {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.hero-sparkles .sparkle {
  position: absolute;
  border-radius: 50%;
  background: var(--amarillo);
  opacity: 0.8;
  box-shadow: 0 0 6px currentColor;
  animation: twinkle 2.4s ease-in-out infinite;
}

.hero-sparkles .sparkle:nth-child(4n+1) { background: var(--amarillo); color: var(--amarillo); }
.hero-sparkles .sparkle:nth-child(4n+2) { background: var(--rosa); color: var(--rosa); }
.hero-sparkles .sparkle:nth-child(4n+3) { background: var(--morado); color: var(--morado); }
.hero-sparkles .sparkle:nth-child(4n+4) { background: var(--azul); color: var(--azul); }

@keyframes twinkle {
  0%, 100% { opacity: 0.2; transform: scale(0.8); }
  50% { opacity: 1; transform: scale(1.2); }
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 700px;
}

.hero-title {
  font-size: clamp(2rem, 6vw, 3.2rem);
  margin: 0 0 16px;
  line-height: 1.2;
}

.rainbow-text {
  background: linear-gradient(90deg, var(--rojo), var(--naranja), var(--amarillo), var(--verde), var(--azul), var(--morado));
  background-size: 300% auto;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: rainbow-move 6s linear infinite;
}

@keyframes rainbow-move {
  0% { background-position: 0% 50%; }
  100% { background-position: 300% 50%; }
}

.hero-dedication {
  font-size: clamp(1.05rem, 2.6vw, 1.3rem);
  font-weight: bold;
  color: var(--azul-oscuro);
  margin: 0 0 18px;
}

.hero.is-dark .hero-dedication {
  color: #e8e9ff;
}

.grace-name {
  display: inline-block;
  font-weight: 900;
  background: linear-gradient(90deg, #ffd93d, #ff8fd8, #a66bff, #4d9dff, #ffd93d);
  background-size: 300% auto;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: rainbow-move 4s linear infinite, grace-glow 2.5s ease-in-out infinite;
}

@keyframes grace-glow {
  0%, 100% { filter: drop-shadow(0 0 6px rgba(255, 217, 61, 0.55)); }
  50% { filter: drop-shadow(0 0 14px rgba(166, 107, 255, 0.7)); }
}

.hero-subtitle {
  font-size: clamp(1rem, 2.4vw, 1.3rem);
  color: var(--gris-suave);
  margin-bottom: 40px;
}

.hero.is-dark .hero-subtitle {
  color: #cfd2ec;
}

.light-switch {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  background: var(--blanco);
  border: 3px solid var(--amarillo);
  border-radius: 999px;
  padding: 14px 28px;
  font-family: inherit;
  font-weight: bold;
  font-size: 1rem;
  color: var(--azul-oscuro);
  cursor: pointer;
  box-shadow: var(--sombra-suave);
  transition: var(--transicion);
}

.light-switch:hover {
  transform: scale(1.05);
}

.light-switch .bulb {
  font-size: 1.8rem;
  transition: var(--transicion);
  filter: grayscale(100%) opacity(0.6);
}

.light-switch.is-on .bulb {
  filter: none;
  text-shadow: 0 0 20px var(--amarillo);
  animation: bulb-pulse 1.6s ease-in-out infinite;
}

@keyframes bulb-pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.15); }
}

.hero.is-dark .light-switch {
  background: #262a52;
  color: var(--blanco);
  border-color: var(--morado);
}

/* ============================================
   SECCION BIBLICA
   ============================================ */

.biblical-section {
  background: linear-gradient(180deg, var(--blanco), #fff9ec);
}

.bible-quote {
  max-width: 640px;
  margin: 0 auto 36px;
  padding: 28px 32px;
  background: linear-gradient(135deg, #fff6da, #ffe9c2);
  border-left: 8px solid var(--naranja);
  border-radius: var(--radio-medio);
  box-shadow: var(--sombra-suave);
}

.bible-quote p {
  font-size: 1.4rem;
  font-style: italic;
  margin: 0 0 10px;
  color: var(--azul-oscuro);
}

.bible-quote cite {
  display: block;
  text-align: right;
  font-weight: bold;
  color: var(--naranja);
}

.biblical-text {
  max-width: 700px;
  margin: 0 auto;
  font-size: 1.1rem;
  line-height: 1.7;
}

/* ============================================
   DATO CURIOSO: VELOCIDAD DE LA LUZ
   ============================================ */

.fact-section {
  background: linear-gradient(135deg, #1b1f3b, #2a2f5c 60%, #3d2a6b);
}

.fact-card {
  max-width: 640px;
  margin: 0 auto;
  text-align: center;
  background: rgba(255, 255, 255, 0.06);
  border: 2px solid rgba(255, 217, 61, 0.4);
  border-radius: var(--radio-grande);
  padding: 40px 28px;
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.25);
}

.fact-icon {
  display: inline-block;
  font-size: 2.6rem;
  margin-bottom: 12px;
  animation: fact-launch 2.2s ease-in-out infinite;
}

@keyframes fact-launch {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-8px) rotate(-6deg); }
}

.fact-title {
  color: var(--amarillo);
  margin: 0 0 16px;
  font-size: 1.6rem;
}

.fact-text {
  color: #f2f3ff;
  line-height: 1.8;
  font-size: 1.05rem;
  margin: 0 0 14px;
}

.fact-text:last-child {
  margin-bottom: 0;
}

.fact-text strong {
  color: var(--amarillo);
}

/* ============================================
   MENU DE TEMAS
   ============================================ */

.topics-menu {
  background: var(--fondo-claro);
}

.topics-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}

.topic-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  background: var(--blanco);
  border-radius: var(--radio-grande);
  padding: 32px 20px;
  box-shadow: var(--sombra-suave);
  transition: var(--transicion);
  border: 3px solid transparent;
}

.topic-card:hover,
.topic-card:focus-visible {
  transform: translateY(-8px) scale(1.02);
  box-shadow: 0 16px 32px rgba(27, 31, 59, 0.18);
}

.topic-icon {
  font-size: 3rem;
  margin-bottom: 12px;
  display: inline-block;
  transition: transform 0.3s ease;
}

.topic-card:hover .topic-icon,
.topic-card:focus-visible .topic-icon {
  transform: scale(1.15) rotate(-6deg);
}

.topic-card h3 {
  margin: 0 0 10px;
  font-size: 1.15rem;
}

.topic-card p {
  color: var(--gris-suave);
  font-size: 0.95rem;
  flex-grow: 1;
  margin-bottom: 18px;
}

.topic-btn {
  font-weight: bold;
  padding: 8px 18px;
  border-radius: 999px;
  background: var(--fondo-claro);
}

.card-espectro:hover { border-color: var(--rosa); }
.card-espectro .topic-btn { background: #ffe3f3; color: #d6459c; }

.card-espectro-completo:hover { border-color: var(--morado); }
.card-espectro-completo .topic-btn { background: #ece0ff; color: #6b3fd4; }

.card-comportamiento:hover { border-color: var(--azul); }
.card-comportamiento .topic-btn { background: #e2f0ff; color: #1a6fd4; }

.card-ojo:hover { border-color: var(--morado); }
.card-ojo .topic-btn { background: #f0e6ff; color: #7b3fe4; }

.card-arcoiris:hover { border-color: var(--verde); }
.card-arcoiris .topic-btn { background: #e0f8e6; color: #2a9e4f; }

/* ============================================
   SECCIONES DE CONTENIDO (placeholders)
   ============================================ */

.content-section {
  scroll-margin-top: 80px;
  padding-top: 20px;
}

.theme-espectro { background: linear-gradient(180deg, #fff0f8, var(--fondo-claro)); }
.theme-espectro-completo { background: linear-gradient(180deg, #f1eaff, var(--fondo-claro)); }
.theme-comportamiento { background: linear-gradient(180deg, #eef6ff, var(--fondo-claro)); }
.theme-ojo { background: linear-gradient(180deg, #f5eeff, var(--fondo-claro)); }
.theme-arcoiris { background: linear-gradient(180deg, #eafff1, var(--fondo-claro)); }

.section-lead {
  max-width: 680px;
  margin: 0 auto 40px;
  text-align: center;
  font-size: 1.1rem;
  line-height: 1.7;
  color: var(--gris-suave);
}

/* ---- Laboratorio del espectro (Fase 2) ---- */

.spectrum-lab {
  max-width: 640px;
  margin: 0 auto 40px;
  background: var(--blanco);
  border-radius: var(--radio-grande);
  padding: 32px 24px;
  box-shadow: var(--sombra-suave);
}

.display-box {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  height: 160px;
  border-radius: var(--radio-medio);
  background: rgb(76, 214, 118);
  color: var(--blanco);
  text-shadow: 0 1px 6px rgba(0, 0, 0, 0.35);
  transition: background 0.15s ease;
  margin-bottom: 20px;
}

.display-box.dark-text {
  color: var(--azul-oscuro);
  text-shadow: 0 1px 4px rgba(255, 255, 255, 0.5);
}

.wavelength-value {
  font-size: 1.8rem;
  font-weight: bold;
}

.color-name {
  font-size: 1.2rem;
}

.wave-canvas-wrap {
  width: 100%;
  height: 90px;
  margin-bottom: 24px;
  border-radius: var(--radio-medio);
  background: var(--fondo-claro);
  overflow: hidden;
}

.wave-canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.slider-wrap {
  margin-bottom: 16px;
}

.slider-label {
  display: block;
  text-align: center;
  font-weight: bold;
  margin-bottom: 10px;
}

.wavelength-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 14px;
  border-radius: 999px;
  background: linear-gradient(
    90deg,
    #8b00ff 0%,
    #4b0082 8%,
    #0000ff 20%,
    #00bfff 32%,
    #00ff00 45%,
    #ffff00 62%,
    #ff9f43 78%,
    #ff0000 100%
  );
  outline: none;
  cursor: pointer;
}

.wavelength-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: var(--blanco);
  border: 4px solid var(--azul-oscuro);
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.25);
}

.wavelength-slider::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--blanco);
  border: 4px solid var(--azul-oscuro);
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.25);
}

.slider-legend {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--gris-suave);
  text-align: center;
  margin-top: 10px;
}

.color-fact {
  text-align: center;
  font-weight: bold;
  color: var(--azul-oscuro);
  margin: 0;
}

.explanation-box {
  max-width: 680px;
  margin: 0 auto;
  background: linear-gradient(135deg, #eef6ff, #f5eeff);
  border-radius: var(--radio-grande);
  padding: 28px 28px;
  box-shadow: var(--sombra-suave);
}

.explanation-box h3 {
  margin-top: 0;
  text-align: center;
}

.explanation-box p {
  line-height: 1.7;
  font-size: 1.05rem;
  margin-bottom: 0;
}

/* ---- Laboratorio de fenómenos y lentes (Fase 3) ---- */

.small-lead {
  margin-bottom: 24px;
}

.phenomena-lab,
.lens-lab {
  max-width: 640px;
  margin: 0 auto 40px;
  background: var(--blanco);
  border-radius: var(--radio-grande);
  padding: 28px 24px;
  box-shadow: var(--sombra-suave);
}

.subsection-title {
  text-align: center;
  margin-top: 0;
}

.phenomena-buttons,
.lens-buttons {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-bottom: 20px;
}

.phenomena-btn,
.lens-btn {
  font-family: inherit;
  font-weight: bold;
  font-size: 0.95rem;
  padding: 10px 18px;
  border-radius: 999px;
  border: 3px solid transparent;
  background: var(--fondo-claro);
  color: var(--azul-oscuro);
  cursor: pointer;
  transition: var(--transicion);
}

.phenomena-btn:hover,
.lens-btn:hover {
  transform: translateY(-2px);
}

.phenomena-btn.is-active,
.lens-btn.is-active {
  background: var(--amarillo);
  border-color: var(--naranja);
}

.angle-control {
  max-width: 420px;
  margin: 0 auto 20px;
  text-align: center;
}

.angle-readout {
  margin: 10px 0 0;
  font-weight: bold;
  color: var(--azul-oscuro);
  font-size: 0.95rem;
}

.angle-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 14px;
  border-radius: 999px;
  outline: none;
  cursor: pointer;
  touch-action: manipulation;
}

.angle-slider-mirror {
  background: linear-gradient(90deg, #dfe6ff, #4d9dff);
}

.angle-slider-water {
  background: linear-gradient(90deg, #cdeaff, #1a6fd4);
}

.angle-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--blanco);
  border: 4px solid var(--azul-oscuro);
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.25);
}

.angle-slider::-moz-range-thumb {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--blanco);
  border: 4px solid var(--azul-oscuro);
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.25);
}

.phenomena-canvas-wrap {
  width: 100%;
  height: 260px;
  margin-bottom: 20px;
  border-radius: var(--radio-medio);
  background: var(--fondo-claro);
  overflow: hidden;
}

.lens-canvas-wrap {
  width: 100%;
  height: 220px;
  margin-bottom: 16px;
  border-radius: var(--radio-medio);
  background: var(--fondo-claro);
  overflow: hidden;
}

.phenomena-canvas,
.lens-canvas {
  display: block;
  width: 100%;
  height: 100%;
}

.phenomena-explanation {
  text-align: center;
}

.phenomena-explanation h3 {
  margin: 0 0 10px;
}

.phenomena-explanation p {
  line-height: 1.7;
  font-size: 1.02rem;
  color: var(--azul-oscuro);
  margin: 0;
}

.coming-soon {
  max-width: 520px;
  margin: 0 auto;
  text-align: center;
  background: var(--blanco);
  border-radius: var(--radio-grande);
  padding: 36px 24px;
  box-shadow: var(--sombra-suave);
}

.coming-icon {
  font-size: 2.6rem;
  display: block;
  margin-bottom: 14px;
}

.coming-soon p {
  font-size: 1.05rem;
  line-height: 1.6;
  color: var(--gris-suave);
  margin: 0;
}

.section-nav-flow {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px 20px;
  max-width: 640px;
  margin: 32px auto 0;
}

.back-link,
.next-link {
  font-weight: bold;
}

.back-link {
  color: var(--azul);
}

.next-link {
  color: var(--verde);
  margin-left: auto;
}

.back-link:hover,
.next-link:hover {
  text-decoration: underline;
}

/* ============================================
   OJO HUMANO (Fase 4)
   ============================================ */

.eye-lab {
  max-width: 640px;
  margin: 0 auto 32px;
  background: var(--blanco);
  border-radius: var(--radio-grande);
  padding: 28px 24px;
  box-shadow: var(--sombra-suave);
  text-align: center;
}

.eye-diagram,
.cell-diagram {
  width: 100%;
  margin-bottom: 16px;
}

.eye-diagram svg,
.cell-diagram svg {
  width: 100%;
  height: auto;
  display: block;
}

.eye-sclera {
  fill: #fbfcff;
  stroke: var(--gris-suave);
  stroke-width: 2;
}

.eye-cornea {
  fill: rgba(77, 157, 255, 0.18);
  stroke: var(--azul);
  stroke-width: 3;
}

.eye-iris {
  fill: rgba(166, 107, 255, 0.55);
  stroke: var(--morado);
  stroke-width: 2;
}

.eye-pupil {
  fill: var(--azul-oscuro);
}

.eye-lens {
  fill: rgba(77, 157, 255, 0.35);
  stroke: var(--azul);
  stroke-width: 2.5;
}

.eye-retina {
  fill: none;
  stroke: var(--rosa);
  stroke-width: 8;
  stroke-linecap: round;
}

.eye-retina-cells line {
  stroke: var(--rojo);
  stroke-width: 3;
  stroke-linecap: round;
}

.eye-nerve {
  fill: #ffe9c2;
  stroke: var(--naranja);
  stroke-width: 2;
}

.eye-ray {
  fill: none;
  stroke: var(--naranja);
  stroke-width: 2;
  opacity: 0.85;
}

.eye-ray-pulse {
  fill: var(--amarillo);
  filter: drop-shadow(0 0 6px var(--amarillo));
}

.eye-label {
  font-size: 11px;
  fill: var(--gris-suave);
  text-anchor: middle;
  font-family: var(--fuente-principal);
}

.eye-caption {
  max-width: 560px;
  margin: 0 auto;
  line-height: 1.7;
  color: var(--azul-oscuro);
}

.cell-buttons {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-bottom: 20px;
}

.cell-btn {
  font-family: inherit;
  font-weight: bold;
  font-size: 0.9rem;
  padding: 9px 16px;
  border-radius: 999px;
  border: 3px solid transparent;
  background: var(--fondo-claro);
  color: var(--azul-oscuro);
  cursor: pointer;
  transition: var(--transicion);
}

.cell-btn:hover {
  transform: translateY(-2px);
}

.cell-btn.is-active {
  background: var(--amarillo);
  border-color: var(--naranja);
}

.cell-group {
  transition: opacity 0.3s ease;
}

.cell-group.cell-dim {
  opacity: 0.25;
}

.cell-group.cell-active {
  opacity: 1;
}

.cell-shape.cell-l { fill: var(--rojo); }
.cell-shape.cell-m { fill: var(--verde); }
.cell-shape.cell-s { fill: var(--azul); }
.cell-shape.cell-rod { fill: #9a9fc2; }

.cell-label {
  font-size: 11px;
  fill: var(--gris-suave);
  text-anchor: middle;
  font-family: var(--fuente-principal);
}

/* ============================================
   ESPECTRO ELECTROMAGNETICO COMPLETO
   ============================================ */

.em-lab {
  max-width: 720px;
  margin: 0 auto 32px;
  background: var(--blanco);
  border-radius: var(--radio-grande);
  padding: 28px 24px;
  box-shadow: var(--sombra-suave);
  text-align: center;
}

.em-diagram {
  width: 100%;
  margin-bottom: 18px;
  overflow-x: auto;
}

.em-diagram svg {
  width: 100%;
  height: auto;
  display: block;
  min-width: 480px;
}

.em-wave {
  fill: none;
  stroke: rgba(255, 255, 255, 0.85);
  stroke-width: 2.5;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.em-band {
  stroke: rgba(27, 31, 59, 0.15);
  stroke-width: 1.5;
}

.em-band-micro { fill: url(#microGradient); }
.em-band-infra { fill: url(#infraGradient); }
.em-band-visible { fill: url(#visibleGradient); }
.em-band-uv { fill: url(#uvGradient); }
.em-band-xray { fill: url(#xrayGradient); }

.em-icon {
  font-size: 26px;
  text-anchor: middle;
}

.em-label {
  font-size: 13px;
  font-weight: bold;
  fill: var(--azul-oscuro);
  text-anchor: middle;
  font-family: var(--fuente-principal);
}

.em-caption {
  font-size: 10px;
  fill: var(--gris-suave);
  text-anchor: middle;
  font-family: var(--fuente-principal);
}

/* ============================================
   ARCOIRIS (Fase 4)
   ============================================ */

.rainbow-lab {
  max-width: 640px;
  margin: 0 auto 32px;
}

.rainbow-scene,
.drop-diagram {
  background: var(--blanco);
  border-radius: var(--radio-grande);
  padding: 20px;
  box-shadow: var(--sombra-suave);
  margin-bottom: 20px;
}

.rainbow-scene svg,
.drop-diagram svg {
  width: 100%;
  height: auto;
  display: block;
}

.rainbow-arcs {
  fill: none;
  animation: rainbow-shimmer 5s ease-in-out infinite;
}

@keyframes rainbow-shimmer {
  0%, 100% { opacity: 0.85; }
  50% { opacity: 1; }
}

.arc-band {
  fill: none;
  stroke-width: 9;
  stroke-linecap: round;
}

.arc-red { stroke: #ff6b6b; }
.arc-orange { stroke: #ff9f43; }
.arc-yellow { stroke: #ffd93d; }
.arc-green { stroke: #4ecb71; }
.arc-blue { stroke: #4d9dff; }
.arc-violet { stroke: #a66bff; }

.rainbow-sun {
  fill: var(--amarillo);
}

.rainbow-sun-rays line {
  stroke: var(--amarillo);
  stroke-width: 3;
  stroke-linecap: round;
}

.rainbow-cloud ellipse {
  fill: #ffffff;
  stroke: #d7dbef;
  stroke-width: 1.5;
}

.drop-line {
  stroke: var(--azul);
  stroke-width: 3;
  stroke-linecap: round;
  transform-box: fill-box;
  transform-origin: center;
  animation: drop-fall 1.4s ease-in infinite;
}

.drop-2 { animation-delay: 0.3s; }
.drop-3 { animation-delay: 0.6s; }
.drop-4 { animation-delay: 0.9s; }

@keyframes drop-fall {
  0% { transform: translateY(-6px); opacity: 0; }
  30% { opacity: 1; }
  100% { transform: translateY(18px); opacity: 0; }
}

.raindrop-shape {
  fill: rgba(77, 157, 255, 0.18);
  stroke: var(--azul);
  stroke-width: 2.5;
}

.drop-ray-in {
  stroke: var(--amarillo);
  stroke-width: 2.5;
  fill: none;
}

.drop-ray-inside {
  stroke: #ffffff;
  stroke-width: 2;
  fill: none;
  stroke-dasharray: 4 4;
}

.drop-ray-pulse {
  fill: var(--amarillo);
  filter: drop-shadow(0 0 6px var(--amarillo));
}

.drop-ray-out {
  stroke-width: 3;
  stroke-linecap: round;
}

.drop-ray-red { stroke: #ff6b6b; }
.drop-ray-orange { stroke: #ff9f43; }
.drop-ray-yellow { stroke: #ffd93d; }
.drop-ray-green { stroke: #4ecb71; }
.drop-ray-blue { stroke: #4d9dff; }
.drop-ray-violet { stroke: #a66bff; }

.covenant-section {
  max-width: 100%;
  border-radius: var(--radio-grande);
  margin: 0 auto 32px;
}

/* ============================================
   FOOTER
   ============================================ */

.site-footer {
  text-align: center;
  padding: 28px 20px;
  background: var(--azul-oscuro);
  color: var(--blanco);
  font-size: 0.95rem;
}

/* ============================================
   RESPONSIVE
   ============================================ */

@media (max-width: 720px) {
  .menu-toggle {
    display: flex;
  }

  .main-nav {
    display: none;
    width: 100%;
    flex-direction: column;
    gap: 8px;
    margin-top: 12px;
  }

  .main-nav.is-open {
    display: flex;
  }

  .nav-link {
    text-align: center;
  }

  .section-inner {
    padding: 44px 18px;
  }

  .hero {
    min-height: 80vh;
  }

  .spectrum-lab {
    padding: 24px 16px;
  }

  .display-box {
    height: 130px;
  }

  .wavelength-value {
    font-size: 1.5rem;
  }

  .phenomena-lab,
  .lens-lab {
    padding: 20px 14px;
  }

  .phenomena-canvas-wrap {
    height: 220px;
  }

  .lens-canvas-wrap {
    height: 190px;
  }

  .phenomena-btn,
  .lens-btn {
    font-size: 0.85rem;
    padding: 8px 14px;
  }

  .section-nav-flow {
    flex-direction: column;
    text-align: center;
  }

  .next-link {
    margin-left: 0;
  }

  .eye-lab {
    padding: 20px 14px;
  }

  .cell-btn {
    font-size: 0.8rem;
    padding: 7px 12px;
  }

  .rainbow-scene,
  .drop-diagram {
    padding: 14px;
  }

  .logo {
    font-size: 1.05rem;
    gap: 8px;
  }

  .logo-icon {
    font-size: 1.4rem;
  }

  .light-switch {
    border-radius: var(--radio-grande);
    padding: 12px 20px;
    gap: 10px;
  }

  .switch-label {
    font-size: 0.9rem;
  }

  .fact-card {
    padding: 28px 18px;
  }

  .em-lab {
    padding: 20px 14px;
  }
}

@media (max-width: 380px) {
  .hero-title {
    font-size: 1.7rem;
  }

  .light-switch {
    flex-direction: column;
    text-align: center;
    padding: 16px;
  }

  .bible-quote {
    padding: 22px 18px;
  }

  .bible-quote p {
    font-size: 1.15rem;
  }

  .topic-card {
    padding: 26px 16px;
  }
}