Cascading Style Sheet (CSS)

HTML document formatting was tedious and complex before CSS because of built-in HTML style attributes. Specifically, styled tags required detailed and repetitious descriptions of the following elements:

• Font colors
• Background styles
• Element alignments
• Borders
• Sizes

CSS structurally defines elements for headings (h1), sub-headings (h2), sub-sub-headings (h3), etc. Element options are available for font, color, emphasis, size, etc.

CSS allows developers to move styling elements to a separate HTML area for clean markup. For example, if a developer wanted to change the font for all h2 headings in an HTML file, a single change could be made to the attached CSS file. If no CSS file was attached, the developer would have to change the font option for each h2 heading in the main HTML file.