header nav > ul > li:nth-of-type(2) > a {
  color: #c33;
  font-weight: 900;
}

section#intro {
  background-image: url(../images/parallax03_950.jpg);
  background-attachment: fixed;
  background-position: center;
  background-repeat: no-repeat;
  background-size: cover;
  min-height: 65vh;
}

section#intro h1,
section#intro h3 {
  max-width: 1050px;
  margin-right: auto;
  margin-left: auto;
}

section.contenido > p,
section.contenido > ul,
section.contenido > ol,
section.contenido > div {
  width: 100%;
  max-width: 1050px;
  margin-right: auto;
  margin-left: auto;
}

section.contenido > p,
section.contenido li {
  font-size: 1.15em;
  line-height: 1.35em;
}

.pasos {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
  padding: 0;
  list-style-position: inside;
}

.pasos li,
.columnas > div,
.opciones > div {
  box-sizing: border-box;
  padding: 1.25rem;
  background-color: #f1f1f1;
}

.columnas,
.opciones {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem;
}

.columnas h3,
.opciones h3 {
  margin-top: 0;
  color: #407dc3;
}

.casos {
  columns: 2;
  column-gap: 3rem;
}

.casos li {
  break-inside: avoid;
  margin-bottom: 1rem;
}

.opciones > div {
  display: flex;
  flex-direction: column;
}

.opciones .boton {
  margin-top: auto;
}

@media screen and (max-width: 700px) {
  section#intro {
    min-height: 75vh;
    background-attachment: scroll;
  }

  .pasos,
  .columnas,
  .opciones {
    grid-template-columns: 1fr;
  }

  .casos {
    columns: 1;
  }
}