border-block-start-width

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.

CSS 属性 border-block-start-width 定义了元素的逻辑块首的边框宽度，并根据元素的书写模式、行内方向和文本朝向对应至实体边框宽度。根据 writing-mode、direction 和 text-orientation 所定义的值，此属性对应于 border-top-width、border-right-width、border-bottom-width 或 border-left-width 属性。

尝试一下

语法

css
/* 边框宽度值 */
border-block-start-width: 5px;
border-block-start-width: thick;

/* 全局值 */
border-block-start-width: inherit;
border-block-start-width: initial;
border-block-start-width: revert;
border-block-start-width: revert-layer;
border-block-start-width: unset;

与此相关的属性有 border-block-end-width、border-inline-start-width 和 border-inline-end-width，这些属性定义了元素其他边框的宽度。

初始值medium
适用元素所有元素
是否是继承属性否
Percentageslogical-width of containing block
计算值absolute length; 0 if the border style is none or hidden
动画类型按计算值的类型

取值

<'border-width'>

边框宽度。见 border-width。

形式定义

初始值medium
适用元素所有元素
是否是继承属性否
Percentageslogical-width of containing block
计算值absolute length; 0 if the border style is none or hidden
动画类型按计算值的类型

形式语法

border-block-start-width = 
  <line-width>  

<line-width> = 
  <length [0,∞]>  |
  thin            |
  medium          |
  thick

示例

竖排文本的边框宽度

HTML

html
<div>
  <p class="exampleText">示例文本</p>
</div>

CSS

css
div {
  background-color: yellow;
  width: 120px;
  height: 120px;
}

.exampleText {
  writing-mode: vertical-lr;
  border: 1px solid blue;
  border-block-start-width: 5px;
}

结果

规范

Specification
CSS Logical Properties and Values Level 1
# border-width

浏览器兼容性

BCD tables only load in the browser

参见