The @font-feature-valuesCSSat-rule allows authors to use a common name in font-variant-alternates for feature activated differently in OpenType. It allows to simplify the CSS when using several fonts.
color is a CSS media feature whose value is the <integer> number of bits per color component (red, green, blue) of the feature. CSS colors can either be defined in hexidecimal format or in an RGB format.
color-index is a CSS media feature whose value is the <integer> number of entries in the output device's color lookup table, or zero if the device does not use such a table.
monochrome is a CSS media feature whose value is the <integer> number of bits per pixel in the output device's monochrome frame buffer, or 0 if the device is not monochrome.
overflow-block is a CSS media feature that can be used to check how the output device handles content that overflows the viewport along the block axis.
scan is a CSS media feature that can be used to check what the scanning process (if any) of the output device is. The word scanning used in this context is not the same as with scanning a book or document into an image format using a scanner. Scanning here refers to the process in which an image is painted into a television (or other device) screen.
width is a CSS media feature that can be used to apply styles conditionally based on the width of the viewport. The width must be specified as a <length> value.</length>
Media Queries is a module of CSS that defines expressions allowing to tailor presentations to a specific range of output devices without changing the content itself.
The basic goal of the Cascading Stylesheet (CSS) language is to allow a browser engine to paint elements of the page with specific features, like colors, positioning, or decorations. The CSS syntax reflects this goal and its basic building blocks are:
getDefaultComputedStyle() gives the default computed values of all the CSS properties of an element, ignoring author styling. That is, only user-agent and user styles are taken into account.