* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: #f9f9f9;
  color: #1a2d5a;
  line-height: 1.6;
  padding: 20px 0 40px;
}

/* ==== CONTENEDOR PRINCIPAL ==== */
#contenedor {
  width: 95%;
  max-width: 1000px;
  margin: 40px auto;
  padding: 30px 25px;
  background-color: #eaf3fb;
  border: 1px solid #ccc;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
  border-radius: 10px;
}

/* ==== ENCABEZADO Y NAVEGACIÓN ==== */
header h1 {
  font-size: 2em;
  color: #1a2d5a;
  text-align: center;
  margin-bottom: 10px;
}

nav ul {
  list-style: none;
  padding: 0;
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-bottom: 30px;
  flex-wrap: wrap;
}

nav ul li a {
  text-decoration: none;
  color: #2c3e50;
  font-weight: bold;
  padding: 8px 12px;
  border-radius: 5px;
  transition: background-color 0.3s;
}

nav ul li a:hover {
  background-color: #d6eaf8;
}

/* ==== CONTENIDO PRINCIPAL ==== */
.contenido h2 {
  font-size: 1.5em;
  color: #1a2d5a;
  margin-bottom: 15px;
  text-align: center;
  border-bottom: 2px solid #b0c4de;
  padding-bottom: 10px;
}

.contenido p {
  font-size: 1.1em;
  background-color: #f5f5f5;
  padding: 12px 16px;
  margin-bottom: 18px;
  border-left: 4px solid #b0c4de;
  border-radius: 5px;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.03);
  text-align: justify;
}

/* ==== PIE DE PÁGINA ==== */
footer {
  text-align: center;
  margin-top: 40px;
  font-size: 0.9em;
  color: #777;
}

/* ======== RESPONSIVE DESIGN ======== */
@media (max-width: 768px) {
  #contenedor {
    padding: 20px 15px;
    margin: 20px auto;
  }

  nav ul {
    flex-direction: column;
    align-items: center;
    gap: 10px;
  }

  header h1 {
    font-size: 1.6em;
  }

  .contenido h2 {
    font-size: 1.3em;
  }

  .contenido p {
    font-size: 1em;
    padding: 10px 14px;
  }
}

@media (max-width: 480px) {
  header h1 {
    font-size: 1.4em;
  }

  .contenido h2 {
    font-size: 1.2em;
  }

  .contenido p {
    font-size: 0.95em;
    padding: 10px;
  }

  nav ul li a {
    font-size: 0.95em;
    padding: 6px 10px;
  }
}