min-height

CSS属性 min-height 通常用来设置一个元素的最小高度。这个属性（min-height）不允许一个元素的高度（height）小于这个元素指定的最小高度（min-height）。

/* <length> value */
min-height: 3.5em;

/* <percentage> value */
min-height: 10%;

/* Keyword values */
min-height: max-content;
min-height: min-content;
min-height: fit-content;
min-height: fill-available;

/* Global values */
min-height: inherit;
min-height: initial;
min-height: unset;

任何时刻，只要某元素的min-height的值比当前的max-height 和height大，那么该元素的高度就被设定为min-height的值。

初始值	`auto`
适用元素	all elements but non-replaced inline elements, table columns, and column groups
是否是继承属性	否
Percentages	The percentage is calculated with respect to the height of the generated box's containing block. If the height of the containing block is not specified explicitly (i.e., it depends on content height), and this element is not absolutely positioned, the percentage value is treated as `0`.
适用媒体	visual
计算值	the percentage as specified or the absolute length
Animation type	a length, percentage or calc();
正规顺序	the unique non-ambiguous order defined by the formal grammar

Syntax

Values

<length>: 当最小高度为是一个有具体数值的时候，赋值将会使这个属性的声明无效。
<percentage>: 当最小高度是一个本身块级元素高度的百分比的时候，赋值将会使这个属性声明无效。

auto: auto 是flex元素的默认最小高度，为其他布局提供了更多合理的大于0的默认数值。

max-content: 固有的建议高度。
min-content: 固有的最低高度。
fill-available: 充当容器的块的高度减掉水平方向的边距、边框、以及填充宽度。某些浏览器还在使用老的关键词，available。
fit-content: 根据CSS3的盒子模型，这个属性等同于min-content。CSS3的尺寸大小控制定义了一个更复杂的算法，但是目前即使在试验层面上，也没有浏览器支持。

Formal syntax

<length> | <percentage> | auto | max-content | min-content | fit-content | fill-available

Examples

table { min-height: 75%; }

form { min-height: 0; }

Specifications

Specification	Status	Comment
CSS Intrinsic & Extrinsic Sizing Module Level 3 min-height	Working Draft	Adds the `max-content`, `min-content`, `fit-content`, and `fill-available` keywords. Both CSS3 Box and CSS3 Writing Modes drafts defined at some point these keywords. These drafts are superseded by this spec.
CSS Flexible Box Layout Module min-height	Candidate Recommendation	Added the `auto` keyword and used it as the initial value.
CSS Transitions min-height	Working Draft	Defines `min-height` as animatable.
CSS Level 2 (Revision 1) min-height	Recommendation	Initial definition

Browser compatibility

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help!

Desktop
Mobile

Feature	Chrome	Edge	Firefox (Gecko)	Internet Explorer	Opera	Safari (WebKit)
Basic support	1.0	(Yes)	3.0 (1.9)	7.0 [3]	4.0	1.0 2.0.2 (416) for positioned elements
applies to `<table>` [1]	未实现	未实现	(Yes)	未实现	(Yes)	未实现
`max-content`, `min-content`, `fit-content`, and `fill-available`	未实现	未实现	未实现	未实现	未实现	9
`auto`已废弃 Gecko 22	21.0	?	16.0 (16.0)	未实现	12.10	未实现
`auto` as initial value已废弃 Gecko 22	21.0	?	18.0 (18.0)	未实现	12.10	未实现

Feature	Android	Edge	Firefox Mobile (Gecko)	IE Phone	Opera Mobile	Safari Mobile
Basic support	?	(Yes)	?	?	?	9

[1] CSS 2.1 explicitly leaves the behavior of min-height with <table> undefined. Therefore any behavior is CSS2.1-compliant; newer CSS specifications may define this behavior, so Web developers shouldn't rely on a specific one now.

[2] Due to bug (bug 307866) Firefox doesn't handle min-height on elements with display: table-*.

[3] In Internet Explorer 10-11 (but not 12+), a min-height declaration on a column-direction flex container doesn't apply to the container's flex items. See Flexbug #3 for more info.