Space Characters
Name	Entity	Width	Alias
Non-Breaking Space	 	[ ]	no-break space, NBSP
Narrow No-Break Space	 	[ ]	NNBSP
En Space	 	[ ]
Em Space	 	[ ]
3-Per-Em Space	 	[ ]	1/3 em space
4-Per-Em Space	 	[ ]	1/4 em space
6-Per-Em Space	 	[ ]	1/6 em space
Figure Space	 	[ ]	numeric space
Punctuation Space	 	[ ]
Medium Mathematical Space	 	[ ]	medium space, MMSP
Thick Space	  	[  ]	medium mathematical space, hair space
Thin Space	 	[ ]
Hair Space	 	[ ]	very thin space
Whitespace	 	[ ]	space, SP
Ideographic Space	　	[　]
Tag Space	󠀠	[󠀠]
Zero Width Space	​	[​]	negative space, ZWSP
Zero Width No-Break Space		[]	BOM, ZWNBSP
Zero Width Joiner	‍	[‍]
Zero Width Non-Joiner	‌	[‌]
Word Joiner	⁠	[⁠]	no break
Invisible Times	⁢	[⁢]
Invisible Separator	⁣	[⁣]	invisible comma

Length Units
Name	Abbr.	Definition		Size
element	em	Font-Relative	font-size of element/root	[]
	rem			[]
line height	lh		line-height of element/root	[]
	rlh			[]
character	ch		width of `0` character in element's/root's font	[]
	rch			[]
X-height	ex		height of letter x in element's/root's font	[]
	rex			[]
capital letter	cap		capital letter-height of element's/root's font	[]
	rcap			[]
international character	ic		average full-glyph width (based on CJK character `水` (U+6C34)) in element's/root's font	[]
	ric			[]
Small	sv*	Viewport-Relative	viewport size keywords	[]
Large	lv*			[]
Dynamic	dv*			[]
Default	N/A			[]
viewport width	vw		1% of viewport's width/height	[]
viewport height	vh			[]
viewport inline	vi		1% of viewport's size in root's inline-axis/block-axis	[]
viewport block	vb			[]
viewport minimum	vmin		1% of viewport's width or height, whichever is smaller/larger	[]
viewport maximum	vmax			[]
container query width	cqw	Container Query	1% of the queried container's width/height	[]
container query height	cqh			[]
container query inline	cqi		1% of the queried container's inline/block (width/height in horizontal writing-mode) size	[]
container query block	cqb			[]
container query minimum	cqmin		the smaller/larger value of either the queried container's inline or block size	[]
container query maximum	cqmax			[]
centimeter	cm	Absolute	1cm  =  37.8px  =  ²⁵.²⁄₆₄in	[]
millimeter	mm		1mm  =  ⅒cm	[]
quarter-millimeter	Q		1Q  =  ¹⁄₄₀cm	[]
inch	in		1in  =  2.54cm  =  96px	[]
pica	pc		1pc  =  ⅙in	[]
point	pt		1pt  =  ¹⁄₇₂in	[]
pixel	px		1px  =  ¹⁄₉₆in	[]