:root {
  /* Colores base */
  --clr-light-bg: #e6f0f3; /* azul muy claro */
  --clr-dark-bg: #132f2f; /* verde azulado oscuro */
  --clr-light-card: #d0e6db; /* verde agua claro */
  --clr-dark-card: #1a3a3a; /* verde azulado medio */
  --clr-light-text: #1b3b36; /* verde oscuro suave */
  --clr-dark-text: #a9c1b8; /* verde grisáceo claro */

  --clr-primary: #4a90e2; /* azul vivo */
  --clr-primary-dark: #438761; /* verde bosque */

  --clr-shadow-light: rgba(74, 144, 226, 0.3);
  --clr-shadow-dark: rgba(45, 90, 75, 0.6);

  --transition-speed: 0.4s;
  --border-radius: 18px;
  --max-content-width: 1200px;
}

/* Estilos generales */
body {
  background: var(--clr-light-bg);
  color: var(--clr-light-text);
  font-family: 'Montserrat', sans-serif;
  margin: 2rem auto;
  max-width: var(--max-content-width);
  padding: 0 1rem;
  transition: background var(--transition-speed), color var(--transition-speed);
}

body.dark {
  background: var(--clr-dark-bg);
  color: var(--clr-dark-text);
}

/* Botón para modo oscuro/claro */
button#toggle {
  background: linear-gradient(135deg, var(--clr-primary), var(--clr-primary-dark));
  border: none;
  color: white;
  padding: 14px 40px;
  font-size: 1.1rem;
  border-radius: var(--border-radius);
  cursor: pointer;
  box-shadow: 0 4px 15px var(--clr-shadow-light);
  transition: box-shadow 0.3s ease, transform 0.2s ease, background var(--transition-speed);
  outline: none;
  position: relative;
  overflow: hidden;
  display: block;
  margin: 0 auto 3rem auto;
}

button#toggle:hover,
button#toggle:focus {
  box-shadow: 0 6px 25px var(--clr-shadow-light);
  transform: scale(1.05);
  background: linear-gradient(135deg, var(--clr-primary-dark), var(--clr-primary));
}

/* Efecto ripple para el botón */
button#toggle .ripple {
  position: absolute;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.6);
  animation: ripple-animation 0.6s linear;
  pointer-events: none;
  transform: scale(0);
}

@keyframes ripple-animation {
  to {
    transform: scale(4);
    opacity: 0;
  }
}

/* Contenedor de tarjetas con CSS Grid */
.gallery {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

/* Estilo de cada tarjeta */
.card {
  background: var(--clr-light-card);
  border-radius: var(--border-radius);
  box-shadow: 0 12px 30px var(--clr-shadow-light);
  font-family: 'Bebas Neue', cursive;
  font-size: 1.8rem;
  color: var(--clr-primary);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  height: 320px;
  cursor: default;
  opacity: 1;
  transform: none;
  transition: background var(--transition-speed), color var(--transition-speed), box-shadow var(--transition-speed);
}

body.dark .card {
  background: var(--clr-dark-card);
  color: var(--clr-primary-dark);
  box-shadow: 0 12px 30px var(--clr-shadow-dark);
}

/* Icono de tarjeta */
.card .icon {
  font-size: 4rem;
  margin-bottom: 12px;
}

/* Título de tarjeta */
.card h3 {
  font-family: 'Bebas Neue', cursive;
  font-size: 1.8rem;
  margin-bottom: 0.8rem;
  color: var(--clr-primary);
  transition: color var(--transition-speed);
}

body.dark .card h3 {
  color: var(--clr-primary-dark);
}

/* Texto descripción */
.card p {
  font-family: 'Montserrat', sans-serif;
  font-size: 1rem;
  line-height: 1.5;
  color: inherit;
  margin: 0 1rem;
  transition: color var(--transition-speed);
}

/* Responsive para pantallas pequeñas */
@media (max-width: 480px) {
  button#toggle {
    width: 100%;
    padding: 16px;
    font-size: 1.2rem;
  }
}