* 仕様書

[REFS[
- [16] [CITE@en[CSS Values and Units Module Level 4]], [TIME[2020-05-01 10:43:32 +09:00]] <https://drafts.csswg.org/css-values/>
]REFS]

* 相対単位

[8] [[媒体クエリー]]では、[[相対単位]]は[[初期値]]に対するものと解されます [SRC[>>7]]。

* 単位の一覧

[FIG[
[FIGCAPTION[
[1]
[[CSS]] および関係規格の[[単位]]:
]FIGCAPTION]

,[CODE(CSS)@en[[[cc]]]]         ,([[絶対長]]) [[cicero]]
,[CODE(CSS)@en[[[ch]]]] 	,([[フォント相対長]]) 文字幅	,[[css-values]]
,[CODE(CSS)@en[[[cm]]]] 	,([[絶対長]]) [[糎]]	,"[CSS1], [CSS2], [CSS2.1], [[css-values]], [MathML1], [MathML2]"
,[CODE(CSS)@en[[[dd]]]]         ,([[絶対長]]) [[didot]]
,[CODE(CSS)@en[[[deg]]]]	,([[角度]]) [[度]]	,"[[CSS 2.1]], [[css-values]]"
,[CODE(CSS)@en[[[dpcm]]]]	,([[解像度]]) [[ドット毎センチメートル]]	,[[css-values]]
,[CODE(CSS)@en[[[dpi]]]]	,([[解像度]]) [[ドット毎インチ]]	,[[css-values]]
,[CODE(CSS)@en[[[dppx]]]]	,([[解像度]]) [[ドット毎CSS画素]]	,[[css-values]]
,[CODE(CSS)@en[[[em]]]] 	,([[フォント相対長]]) [[M]]	,"[CSS1], [CSS2], [CSS2.1], [[css-values]], [MathML1], [MathML2]"
,[CODE(CSS)@en[[[ex]]]] 	,([[フォント相対長]]) [[x高]]	,"[CSS1], [CSS2], [CSS2.1], [[css-values]], [MathML1], [MathML2]"
,[CODE(CSS)@en[[[gr]]]]         ,([[相対長]]) [[グリッド]]
,[CODE(CSS)@en[[[grad]]]]	,([[角度]]) [[グラジアン]]	,"[[CSS 2.1]], [[css-values]]"
,[CODE(CSS)@en[[[Hz]]]] 	,([[周波数]]) [[ヘルツ]]	,"[[CSS 2.1]], [[css-values]]"
,[CODE(CSS)@en[[[in]]]] 	,([[絶対長]]) [[吋]]	,"[CSS1], [CSS2], [CSS2.1], [[css-values]], [MathML1], [MathML2]"
,[CODE(CSS)@en[[[jpt]]]]        ,([[絶対長]]) [[JIS Z 8305]] [[ポイント]]
,[CODE(CSS)@en[[[kHz]]]]	,([[周波数]]) [[キロヘルツ]]	,"[[CSS 2.1]], [[css-values]]"
,[CODE(CSS)@en[[[lh]]]]         ,([[相対長]]) [[行高]]
,[CODE(CSS)@en[[[mm]]]] 	,([[絶対長]]) [[粍]]	,"[CSS1], [CSS2], [CSS2.1], [[css-values]], [MathML1], [MathML2]"
,[CODE(CSS)@en[[[ms]]]] 	,([[時間]]) [[ミリ秒]]	,"[[CSS 2.1]], [[css-values]]"
,[CODE(CSS)@en[[[pc]]]] 	,([[絶対長]]) [[パイカ]]	,"[CSS1], [CSS2], [CSS2.1], [[css-values]], [MathML1], [MathML2]"
,[CODE(CSS)@en[[[pcw]]]]	,可変列幅	
,[CODE(CSS)@en[[[pt]]]] 	,([[絶対長]]) [[ポイント]]	,"[CSS1], [CSS2], [CSS2.1], [[css-values]], [MathML1], [MathML2]"
,[CODE(CSS)@en[[[pvh]]]]        ,([[相対長]]) [[ページ]]高さの[[百分率]]
,[CODE(CSS)@en[[[pvmax]]]]      ,([[相対長]]) [[ページ]]長辺の[[百分率]]
,[CODE(CSS)@en[[[pvmin]]]]      ,([[相対長]]) [[ページ]]短辺の[[百分率]]
,[CODE(CSS)@en[[[pvw]]]]        ,([[相対長]]) [[ページ]]幅の[[百分率]]
,[CODE(CSS)@en[[[px]]]]		,([[絶対長]]) [[CSS画素]]	,"[CSS1], [CSS2], [CSS2.1], [[css-values]], [MathML1], [MathML2]"
,[CODE(CSS)@en[[[q]]]]          ,([[絶対長]]) [[Q]]
,[CODE(CSS)@en[[[%]]]]	,[[百分率]]	,"[CSS1], [CSS2], [CSS2.1]"
,[CODE(CSS)@en[[[__qem]]]]	,([[フォント相対長]]) [[奇癖em]]	,[[WebKit]]
,[CODE(CSS)@en[[[rad]]]]	,([[角度]]) [[ラジアン]]	,"[[CSS 2.1]], [[css-values]]"
,[CODE(CSS)@en[[[rem]]]]	,([[フォント相対長]]) [[根要素]]の[[M]]	,[[css-values]]
,[CODE(CSS)@en[[[rlh]]]]        ,([[相対長]]) [[根要素]]の[[行高]]
,[CODE(CSS)@en[[[s]]]]  	,([[時間]]) [[秒]]	,"[[CSS 2.1]], [[css-values]]"
,[CODE(CSS)@en[[[turn]]]]	,([[角度]]) [[旋回]]	,[[css-values]]
,[CODE(CSS)@en[[[vh]]]] 	,([[閲覧領域相対長]]) [[閲覧領域]]高さの[[百分率]]	,[[css-values]]
,[CODE(CSS)@en[[[vmax]]]]	,([[閲覧領域相対長]]) [[閲覧領域]]長辺の[[百分率]]	,[[css-values]]
,[CODE(CSS)@en[[[vmin]]]]	,([[閲覧領域相対長]]) [[閲覧領域]]短辺の[[百分率]]	,[[css-values]]
,[CODE(CSS)@en[[[vw]]]] 	,([[閲覧領域相対長]]) [[閲覧領域]]幅の[[百分率]]	,[[css-values]]
,[CODE(CSS)@en[[[wch]]]]        ,([[フォント相対長]]) [[U+3000]] 幅
]FIG]

[17] [CODE[%%]],
[CODE[dip]],
[CODE[*][* (単位)]],
[CODE[#][# (単位)]]


* 歴史

[2]
[CITE@ja[Taken SPC : 翻訳: Units Patch Landed]] ([CODE[2007-02-13 09:24:58 +09:00]] 版) <http://taken.s101.xrea.com/blog/article.php?id=720>
([[名無しさん]] [WEAK[2007-02-13 00:25:55 +00:00]])

[3]
[CITE@EN[Delivery Context: XPath Access Functions 1.0]] ([CODE[2007-07-16 22:51:54 +09:00]] 版) <http://www.w3.org/TR/2007/CR-cselection-xaf-20070725/#sec-units>
([[名無しさん]])

[4]
<IW:SVG:"coords.html#Units">
([[名無しさん]])


[5]
[CITE@en[Unitless CSS Lengths - MozillaWiki]] ([TIME[2006-11-26 00:22:05 +09:00]] 版) <http://wiki.mozilla.org/Unitless_CSS_Lengths>
([[名無しさん]])



[6] [CITE[IRC logs: freenode / #whatwg / 20121005]]
( ([TIME[2012-10-08 21:33:56 +09:00]] 版))
<http://krijnhoetmer.nl/irc-logs/whatwg/20121005#l-671>

[10] [CITE@en[AH Formatter XSL/CSS Extension]]
( ([TIME[2013-07-23 07:02:25 +09:00]] 版))
<http://antennahouse.com/CSSInfo/extension.html#ext-unit-conf>

[11] [CITE@en['''['''css-values''']''' Define the concept of compatible and canonical units, an…]]
( ([[tabatkins]]著, [TIME[2016-06-09 07:49:38 +09:00]]))
<https://github.com/w3c/csswg-drafts/commit/c46c66198ff50ceaca48061f85967926c55a84d1>

[12] [CITE@en['''['''css-values''']''' First stab at trying to fix the definition of compatible…]]
( ([[fantasai]]著, [TIME[2016-06-09 11:04:04 +09:00]]))
<https://github.com/w3c/csswg-drafts/commit/1fed9d86a8eb9ad1670fb5c4cea0f7450bb70898>

[13] [CITE@en['''['''css-values''']''' Per WG resolution, added vi and vb units. For #113.]]
( ([[tabatkins]]著, [TIME[2016-06-23 06:47:28 +09:00]]))
<https://github.com/w3c/csswg-drafts/commit/52468c98e0e96e374ceceecd59d1de0400c23305>

[14] [CITE@en['''['''cssom''']''' Issue 9 makes no sense at all · Issue #1554 · w3c/csswg-drafts]]
([TIME[2018-05-19 11:38:00 +09:00]])
<https://github.com/w3c/csswg-drafts/issues/1554>

[15] [CITE@en[Retiring Obsolete CSS Notes]]
([[Florian Rivoal]]著, [TIME[2018-09-07 00:49:09 +09:00]])
<https://lists.w3.org/Archives/Public/www-style/2018Sep/0003.html>


[REFS[
- [9] [CITE@en[CSS Values and Units Module Level 3]] ([TIME[2013-08-23 23:29:23 +09:00]] 版) <http://dev.w3.org/csswg/css-values/>
- [7] [CITE@en[Media Queries Level 4]] ([TIME[2013-07-25 22:52:42 +09:00]] 版) <http://w3c-test.org/csswg/mediaqueries/#units>
]REFS]