CSS Grid layout contains design features targeted at web application developers. The CSS grid can be used to achieve many different layouts. It excels at dividing a page into major regions, or defining the relationship in terms of size, position, and layer, between parts of a control built from HTML primitives.
The @document CSS at-rule restricts the style rules contained within it based on the URL of the document. It is designed primarily for user style sheets. A @document rule can specify one or more matching functions. If any of the functions apply to a URL, the rule will take effect on that URL.
The @import CSS at-rule is used to import style rules from other style sheets. These rules must precede all other types of rules, except @charset rules; as it is not a nested statement, @import cannot be used inside conditional group at-rules.
The @media CSS at-rule associates a set of nested statements, in a CSS block that is delimited by curly braces, with a condition defined by a media query. The @media at-rule may be used not only at the top level of a CSS, but also inside any CSS conditional-group at-rule.
The width CSS descriptor is shorthand for setting both the min-width and the max-width of the viewport. By providing one viewport length value, that value will determine both the min-width and the max-width to the value provided.
An at-rule is a CSS statement beginning with an at sign, '@' (U+0040 COMMERCIAL AT), followed by an identifier and includes everything up to the next semi-colon, ';' (U+003B SEMICOLON), or the next CSS block, whichever comes first.
CSS Columns is a module of CSS that defines a multi-column layout, allowing to express how content should flow between columns and how gaps and rules are handled.
CSS3 is the latest evolution of the Cascading Style Sheets language and aims at extending CSS2.1. It brings a lot of long-awaited novelties, like rounded corners, shadows, gradients, transitions or animations, as well as new layouts like multi-columns, flexible box or grid layouts. Experimental parts are vendor-prefixed and should either be avoided in production environments, or used with extreme caution as both their syntax and semantics can change in the future.
The font-smooth CSS property controls the application of anti-aliasing when fonts are rendered.
This CSS Reference shows the basic syntax of a CSS rule; lists all standard CSS properties, pseudo-classes and pseudo-elements, @-rules, units, and selectors, all together in alphabetical order, as well as just the selectors by type; and allows you to quickly access detailed information for each of them. It not only lists the CSS 1 and CSS 2.1 properties, but also is a CSS3 reference that links to any CSS3 property and concept standardized, or already stabilized.  Also included is a brief DOM-CSS / CSSOM reference.
In CSS, a replaced element is an element whose representation is outside the scope of CSS. These are a type of external object whose representation is independent of the CSS. Typical replaced elements are <img>, <object>, <video> or form elements like <textarea> and <input>. Some elements, like <audio> or <canvas> are replaced elements only in specific cases. Objects inserted using the CSS content properties are anonymous replaced elements.
The specified value of a CSS property is set in one out of three ways.
Controls the actual Selection operation. This doesn't have any effect on content loaded as chrome, except in textboxes. A similar property user-focus was proposed in early drafts of a predecessor of css3-ui but was rejected by the working group.
WebKit supports a number of extensions to CSS that are prefixed with -webkit. All -webkit prefixed properties also work with an -apple prefix.