estilos.css

:root{
  font-size: 16px;
  /* variables --rojoderojos: #ff0000; */
  --main-color: #212121;
  --main-color10: #616161;
  --top-bottom-background: #212429;
}

*{
  /* margin: 0px auto; */
  margin: 0;
  background: #fff;
  /* font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif; */
  font-family: 'Roboto', sans-serif;
  color: var(--main-color);
}
.top-area{
  height: 350px;
  background: linear-gradient(3.36deg, rgba(255,255,255, .5) -63.62%, rgba(255, 255, 255, 0) 80%), url(imagenes_home/patron-1.png);
}
.content-area{
  display: flex;
  padding: 4rem 7.25rem;
}
.content-area header{
  flex: 0.4;
  display: flex;
  flex-direction: column;
  align-items: flex-start;

  font-size: 14px;
  line-height: 24px;
}
header a{
  color: var(--main-color10);
  text-decoration: none;
}
header details summary{
  font-weight: bold;
}
header details ol{
  padding-left: 1rem;
}
header a:hover{
  color: var(--main-color);
}
.content-area main{
  flex: 0.6;
  padding: 0px 2rem;
}
main h1{
  font-size: 60px;
  font-weight: 400;
  line-height: 70px;
  margin-bottom: 1rem;
}
main p{
  font-size: 16px;
  font-weight: 400;
  line-height: 24px;
}

/* ESTILOS PARA LAS SECCIONES DE CONTENIDO */
.section_content{
  width: 100%;
  margin: 20px 0;
  counter-reset: subtitulo-contenido;
}
/* Subtitulos de contenido */
.section_content h4{
  counter-increment: subtitulo-contenido;
}

.section_content h4::before{
  content: counter(subtitulo-contenido)". ";
}

h4::after{
  content: "";
  width: 20px;
  height: 5px;
  background: #000;
  display: inline-block;
}

/* Subtitulos de MAIN */
.main h3{
  font-size: 2rem;
  font-style: normal;
  font-weight: 400;
  line-height: 38px;
  letter-spacing: 0em;
  text-align: left;
}

/* Caja con codigo de ejemplo */
pre{
  background: khaki;
  padding: 40px;
}

/* <<<<<<<<<<<<<<< SEPARADOR  >>>>>>>>>>>>> */
hr{
  margin: 4rem 0;
}

/* <<<<<<<<<<<<<<< PIE DE PAGINA  >>>>>>>>>>>>> */
footer{
  width: 100%;
  height: 150px;
  background: var(--top-bottom-background);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
footer .copy{
  letter-spacing: 5px;
  margin-bottom: 10px;
  color: #fff;
  background: var(--top-bottom-background);
}