CSS rules are made up of selectors and declarations. A selector is used to target an HTML element, while declarations contain rule properties and values that are applied to the targeted element.

Safari supports new properties proposed for CSS level 3. In fact, Safari 1.1 has added support for three new properties: text-shadow property, rgba () colors with alpha values, and the :selection ...

Microsoft has announced that CSS Custom Properties will making their way to its Edge browser in the Windows 10 Creators Update, unlocking "potential for more creative work on the web".