The primary standards that define content on the web are HTML and CSS. HTML, or hypertext markup language, defines the structural components of web content. CSS, or cascading style sheets, defines how the HTML is presented. If you are interested in learning more, visit the home of web standards: W3C.
Inspired by CSS Zen Garden and driven by a desire to showcase what can be done with a mere 1KB of CSS, Jacob Rask, a web developer at Opera Software, created CSS1K about six months ago. Since then the site has showcased 68 different designs, all with stylesheets under 1KB.