HTML
Hypertext Markup Language (HTML) is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScript.
<!DOCTYPE html>
<html lang="es">
<head>
<title>Mi primer HTML</title>
</head>
<body>
<h1>Hola Mundo!</h1>
</body>
</html> 
CSS
CSS (siglas en inglés de Cascading Style Sheets), en español «Hojas de estilo en cascada», es un lenguaje de diseño gráfico para definir y crear la presentación de un documento estructurado escrito en un lenguaje de marcado.
<html>
<head>
<title>Animals Around the World</title>
<link href="style.css" type="text/css" rel="stylesheet">
</head>
<body>
<h1>The Brown Bear</h1>
<p>The brown bear (Ursus arctos) is native to parts of northern Eurasia and North America. Its conservation status is currently "Least Concern." There are many subspecies within the brown bear species, including the Atlas bear and the Himalayan brown bear.</p>
<a href="https://en.wikipedia.org/wiki/Brown_bear">Learn More</a>
<a href="https://en.wikipedia.org/wiki/Brown_bear" target="_blank">
<img src="https://s3.amazonaws.com/codecademy-content/courses/web-101/web101-image_brownbear.jpg" /></a>
</body>
</html>
