* { box-sizing: border-box; }
body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Ubuntu, "Helvetica Neue", Arial, sans-serif;
  margin: 0;
  background: #f4f4f4;
  color: #222;
  line-height: 1.6;
}

header {
  background: #007bff;
  color: #fff;
  text-align: center;
  padding: 1rem 0.5rem;
}
header h1 { margin: 0 0 0.5rem; font-weight: 700; }

nav .menu {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  justify-content: center;
  padding: 0;
  margin: 0;
}
nav .menu a {
  text-decoration: none;
  padding: 0.5rem 0.9rem;
  background: rgba(255,255,255,0.15);
  border-radius: 999px;
  color: #fff;
}
nav .menu a:hover,
nav .menu a:focus { background: rgba(255,255,255,0.3); outline: none; }

main {
  max-width: 980px;
  margin: 2rem auto;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 8px 24px rgba(0,0,0,0.08);
  padding: 1.25rem;
}
main h2 { margin-top: 0; }

article, section {
  margin: 1rem 0;
  padding: 1rem;
  border-radius: 10px;
  background: #e9f5ff; /* Base (general) */
  border-left: 5px solid #007bff;
}

aside {
  background: #f8f9fa;
  padding: 1rem;
  border-left: 5px solid #ddd;
  margin: 1rem 0;
}
blockquote {
  margin: 0;
  font-style: italic;
  color: #666;
}

footer {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 0.75rem 1rem;
  background: #212529;
  color: #fff;
  text-align: center;
}

.seccion-alto-nivel {
  background: #f0e4ff;
  border-left: 5px solid #6c757d;
}
.seccion-bajo-nivel {
  background: #f7f7e9;
  border-left: 5px solid #ffc107;
}
.seccion-scripting {
  background: #f6e6e8;
  border-left: 5px solid #dc3545;
}
.seccion-frameworks {
  background: #e6f6e8;
  border-left: 5px solid #17a2b8;
}

.imagen-contenedor {
  text-align: center;
  margin: 2rem 0;
}
.imagen-contenedor img {
  max-width: 100%;
  height: auto;
  border: 3px solid #ccc;
  border-radius: 8px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
  transition: transform 0.3s ease-in-out;
}
.imagen-contenedor img:hover { transform: scale(1.02); }
.pie-imagen {
  font-size: 0.9em;
  color: #666;
  margin-top: 0.5rem;
}

@media (prefers-reduced-motion: reduce) {
  .imagen-contenedor img { transition: none; }
}
@media (max-width: 640px) {
  main { margin: 1rem; padding: 1rem; }
}
/* Estilos para pantallas pequeñas (celulares) */ 
@media (max-width: 600px) { 
  body {
    font-size: 14px; 
    }
    header, footer {
      text-align: center; 
    } 
  }