For the CSS rules to act properly on your HTML document, it is important that the HTML and the CSS be error-free. If there are any errors in the HTML or in the CSS, the different browsers will react differently, apply the style in an unexpected way, or not apply the style at all. The online HTML and CSS validators listed in the references section make it easy to ensure that the CSS and HTML that make up your documents are error-free. We strongly encourage their use. Viewing this page in different browsers can also be an instructive experience.
Different browsers treat CSS differently.