CSS

====Values====
Values may be keywords, such as "center" or "inherit", or numerical values, such as {{code|code=200px|2=css}} (200 pixels), {{code|code=50vw|2=css}} (50 percent of the viewport width) or {{mono|80%}} (80 percent of the parent element's width).

Color values can be specified with keywords (e.g. "{{code|code=red|2=css}}"), hexadecimal values (e.g. {{code|code=#FF0000|2=css}}, also abbreviated as {{code|code=#F00|2=css}}), RGB values on a 0 to 255 scale (e.g. <code>{{code|code=rgb(255, 0, 0)|2=css}}</code>), RGBA values that specify both color and alpha transparency (e.g. {{code|code=rgba(255, 0, 0, 0.8)|2=css}}), or HSL or HSLA values (e.g. {{code|code=hsl(0 100% 50%)|2=css}}, {{code|code=hsl(0 100% 50% / 0.8)|2=css}}).<ref>{{cite web |url=https://developer.mozilla.org/en-US/docs/Web/CSS/color |title=CSS Color |publisher=MDN Web Docs |date=2024-04-05 |access-date=2024-04-05 |archive-url=https://web.archive.org/web/20240327000753/https://developer.mozilla.org/en-US/docs/Web/CSS/color |archive-date=2024-03-27 |url-status=live }}</ref>

Non-zero numeric values representing linear measures must include a length unit, which is either an alphabetic code or abbreviation, as in <code>200px</code> or <code>50vw</code>; or a percentage sign, as in <code>80%</code>. Some units – <code>cm</code> ([[centimetre]]); <code>in</code> ([[inch]]); <code>mm</code> ([[millimetre]]); <code>pc</code> ([[Pica (typography)|pica]]); and <code>pt</code> ([[Point (typography)|point]]) – are ''absolute'', which means that the rendered dimension does not depend upon the structure of the page; others – <code>em</code> ([[Em (typography)|em]]); <code>ex</code> ([[Ex (typography)|ex]]) and <code>px</code> ([[pixel]]){{clarify|reason=This "such as" is carrying too much weight. The size of a px is relative not to the font size, but to screen resolution and viewing distance. Furthermore, in CSS 3 the "px" becomes the primordial absolute unit as the length units become anchored to it.|date=March 2022}} – are ''relative'', which means that factors such as the font size of a parent element can affect the rendered measurement. These eight units were a feature of CSS 1<ref>{{cite web |url=https://www.w3.org/TR/REC-CSS1-961217#length-units |title=6.1 Length units |work=Cascading Style Sheets, level 1 |date=17 December 1996 |access-date=20 June 2019 |archive-url=https://web.archive.org/web/20190614194847/https://www.w3.org/TR/REC-CSS1-961217#length-units |archive-date=14 June 2019 |url-status=live }}</ref> and retained in all subsequent revisions. The proposed CSS Values and Units Module Level 3 will, if adopted as a W3C Recommendation, provide seven further length units: <code>ch</code>; <code>Q</code>; <code>rem</code>; <code>vh</code>; <code>vmax</code>; <code>vmin</code>; and <code>vw</code>.<ref>{{cite web |url=https://www.w3.org/TR/2019/CR-css-values-3-20190606/#lengths |title=5. Distance Units: the &lt;length&gt; type |work=CSS Values and Units Module Level 3 |date=6 June 2019 |access-date=20 June 2019 |archive-url=https://web.archive.org/web/20190607171702/https://www.w3.org/TR/2019/CR-css-values-3-20190606/#lengths |archive-date=7 June 2019 |url-status=live }}</ref>