CSS entries starting with “A”

Every CSS entry starting with A, grouped by kind. Pseudo-classes, pseudo-elements and types are filed by their first letter, ignoring the leading :, :: or <.

Name	Description
Color
`AccentColor`	System colour: the background of accented controls.
`AccentColorText`	System colour: text on an AccentColor background.
`ActiveText`	System colour: text of a link being activated.
`aliceblue`	Named colour #f0f8ff.
`antiquewhite`	Named colour #faebd7.
`aqua`	Named colour #00ffff, the same as cyan.
`aquamarine`	Named colour #7fffd4.
`azure`	Named colour #f0ffff.
Container feature
`anchored()`	A container query on which position fallback an anchored box uses.
`aspect-ratio`	The width-to-height ratio of the query container.
Descriptor
`additive-symbols`	An @counter-style descriptor: weighted symbols for the additive system.
`ascent-override`	An @font-face descriptor that overrides the font's ascent metric.
Function
`abs()`	The absolute value of its argument.
`acos()`	The angle whose cosine is the given number.
`alpha()`	Changes only the alpha of a colour.
`anchor()`	The position of a side of an anchor element, for inset properties.
`anchor-size()`	The width or height of an anchor element.
`asin()`	The angle whose sine is the given number.
`at-rule()`	An @supports test for whether the browser supports an at-rule.
`atan()`	The angle whose tangent is the given number.
`atan2()`	The angle of a vector given its y and x components.
`attr()`	Substitutes an attribute value, as a string or parsed as a type.
Media feature
`any-hover`	Whether any available input device can hover.
`any-pointer`	Whether any available input is a pointer, and how accurate it is.
`aspect-ratio`	The width-to-height ratio of the viewport.
Property
`accent-color`	The accent colour of native checkboxes, radios, sliders and progress bars.
`align-content`	Distributes free space between flex lines, grid rows or block content.
`align-items`	Aligns every item in the cross or block axis.
`align-self`	Overrides align-items for a single item.
`alignment-baseline`	Which baseline of a box lines up with its parent.
`all`	Resets every property on an element to one CSS-wide keyword.
`anchor-name`	Makes an element an anchor and names it for positioned boxes.
`anchor-scope`	Limits anchor names to an element and its descendants.
`animation`	Shorthand that runs keyframe animations on an element.
`animation-composition`	How animated values combine with the underlying value.
`animation-delay`	How long to wait before an animation starts.
`animation-direction`	Whether animation cycles play forwards, backwards or alternate.
`animation-duration`	How long one cycle of an animation takes.
`animation-fill-mode`	Whether keyframe styles apply before and after an animation runs.
`animation-iteration-count`	How many times an animation runs.
`animation-name`	The names of the keyframes rules to run.
`animation-play-state`	Pauses or resumes an animation.
`animation-range`	Shorthand for the part of a timeline an animation is attached to.
`animation-range-end`	Where on its timeline an animation ends.
`animation-range-start`	Where on its timeline an animation starts.
`animation-timeline`	The timeline that drives an animation, such as a scroll timeline.
`animation-timing-function`	The easing curve between an animation's keyframes.
`animation-trigger`	Connects an element's animations to named triggers.
`appearance`	Whether a form control keeps its native platform look.
`aspect-ratio`	A preferred width-to-height ratio for a box.
Pseudo-class
`:active`	Matches an element while it is being pressed or activated.
`:active-view-transition`	Matches the root element while a view transition is running.
`:active-view-transition-type()`	Matches the root while a view transition of a given type is running.
`:any-link`	Matches every hyperlink, visited or not.
`:autofill`	Matches inputs the browser has filled in automatically.
Pseudo-element
`::after`	Generated content inserted after an element's own content.
`:after`	Legacy single-colon form of ::after from CSS 2.
Type
`<absolute-size>`	Font size keywords from xx-small to xxx-large.
`<alpha-value>`	The opacity of a colour, as a number or percentage.
`<anchor-name>`	The dashed-ident name of an anchor element.
`<angle-percentage>`	Either an angle or a percentage of a full turn.
`<angle>`	A rotation or direction in deg, grad, rad or turn.