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HTML

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CSS

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JavaScript

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Babel includes JSX processing.

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HTML 

              
                <h2>Segunda Guerra Mundial</h2>
<p>
  La Segunda Guerra Mundial (WWII o WW2), también conocida como World War II  (después de la reciente Gran Guerra), fue una guerra global que duró
  <mark>de 1939 a 1945</mark>, aunque los conflictos relacionados comenzaron antes. En ella participaron la gran mayoría de las naciones del mundo -incluidas todas las grandes potencias-, que acabaron formando dos alianzas militares opuestas: los Aliados y el Eje. Fue la guerra más extendida de la historia, e implicó directamente a más de <mark>100 millones de personas de más de 30 países</mark>. En un estado de "guerra total", los principales participantes pusieron toda su capacidad económica, industrial y científica al servicio del esfuerzo bélico, borrando la distinción entre recursos civiles y militares. Marcada por la muerte masiva de civiles, incluidos el
  <mark>Holocausto</mark> (en el que murieron aproximadamente 11 millones de personas) y el bombardeo estratégico de centros industriales y de población (en el que murieron aproximadamente un millón de personas, incluido el uso de dos armas nucleares en combate), se calcula que causó entre 50 y 85 millones de víctimas mortales. Todo ello convirtió a la Segunda Guerra Mundial en el conflicto más mortífero de la historia de la humanidad.
</p>
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CSS 

              
                body {
  font-family: "bookman old style";
}

mark {
  background: cyan;
}
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JS
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999px

Console