block-size

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2021.

* Some parts of this feature may have varying levels of support.

CSS 属性 block-size 根据元素的书写模式定义了元素块的横向或纵向尺寸。根据 writing-mode 的值，此属性对应于 width 或 height 属性。

若为纵向书写模式，则 block-size 的值对应于元素的宽度；否则对应于元素的高度。与此相关的属性为 inline-size，此属性定义了元素另一方向的尺度。

尝试一下

block-size: 150px;
writing-mode: horizontal-tb;

block-size: 150px;
writing-mode: vertical-rl;

block-size: auto;
writing-mode: horizontal-tb;

block-size: auto;
writing-mode: vertical-lr;

<section class="default-example" id="default-example">
  <div class="transition-all" id="example-element">
    This is a box where you can change the block-size.
  </div>
</section>

#example-element {
  display: flex;
  flex-direction: column;
  background-color: #5b6dcd;
  justify-content: center;
  color: #ffffff;
}

语法

css
/* <length> 值 */
block-size: 300px;
block-size: 25em;

/* <percentage> 值 */
block-size: 75%;

/* 关键词值 */
block-size: max-content;
block-size: min-content;
block-size: fit-content(20em);
block-size: auto;

/* 全局值 */
block-size: inherit;
block-size: initial;
block-size: revert;
block-size: revert-layer;
block-size: unset;

取值

block-size 属性的取值与 width 和 height 属性相同。

形式定义

初始值auto
适用元素same as width and height
是否是继承属性否
Percentagesblock-size of containing block
计算值same as width and height
动画类型a length, percentage or calc();

形式语法

block-size = 
  <'width'>  

<width> = 
  auto                                      |
  <length-percentage [0,∞]>                 |
  min-content                               |
  max-content                               |
  fit-content( <length-percentage [0,∞]> )  |
  <calc-size()>                             |
  <anchor-size()>                           

<length-percentage> = 
  <length>      |
  <percentage>  

<calc-size()> = 
  calc-size( <calc-size-basis> , <calc-sum> )  

<anchor-size()> = 
  anchor-size( [ <anchor-name> || <anchor-size> ]? , <length-percentage>? )  

<calc-size-basis> = 
  <intrinsic-size-keyword>  |
  <calc-size()>             |
  any                       |
  <calc-sum>                

<calc-sum> = 
  <calc-product> [ [ '+' | '-' ] <calc-product> ]*  

<anchor-name> = 
  <dashed-ident>  

<anchor-size> = 
  width        |
  height       |
  block        |
  inline       |
  self-block   |
  self-inline  

<calc-product> = 
  <calc-value> [ [ '*' | / ] <calc-value> ]*  

<calc-value> = 
  <number>        |
  <dimension>     |
  <percentage>    |
  <calc-keyword>  |
  ( <calc-sum> )  

<calc-keyword> = 
  e          |
  pi         |
  infinity   |
  -infinity  |
  NaN

示例

竖排文本的块向尺寸

HTML

html
<p class="exampleText">示例文本</p>

CSS

css
.exampleText {
  writing-mode: vertical-rl;
  background-color: yellow;
  block-size: 200px;
}

结果

规范

Specification
CSS Logical Properties and Values Level 1
# dimension-properties
CSS Box Sizing Module Level 4
# sizing-values

浏览器兼容性

参见