CSS 属性 border-block-start-color 定义了元素的逻辑块首的边框颜色，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颜色。根据 {{CSSXref("writing-mode")}}、{{CSSXref("direction")}} 和 {{CSSXref("text-orientation")}} 所定义的值，此属性对应于 {{CSSXref("border-top-color")}}、{{CSSXref("border-right-color")}}、{{CSSXref("border-bottom-color")}} 或 {{CSSXref("border-left-color")}} 属性。

{{InteractiveExample("CSS Demo: border-block-start-color")}}

```css interactive-example-choice border-block-start-color: red; writing-mode: horizontal-tb;


```css interactive-example-choice
border-block-start-color: #32a1ce;
writing-mode: vertical-rl;

```css interactive-example-choice border-block-start-color: rgb(170, 50, 220, 0.6); writing-mode: horizontal-tb;


```css interactive-example-choice
border-block-start-color: hsl(60, 90%, 50%, 0.8);
writing-mode: vertical-lr;

```html interactive-example

This is a box with a border around it. 


```css interactive-example
#example-element {
  background-color: #eee;
  color: #000;
  border: 0.75em solid;
  padding: 0.75em;
  width: 80%;
  height: 100px;
  unicode-bidi: bidi-override;
}

语法

border-block-start-color: blue;
border-block-start-color: #4c5d21;

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

与此相关的属性有 {{CSSXref("border-block-end-color")}}、{{CSSXref("border-inline-start-color")}} 和 {{CSSXref("border-inline-end-color")}}，这些属性定义了元素其他边框的颜色。

取值

  • <'color'>
    • : 见 {{CSSXref("border-color")}}

形式定义

{{CSSInfo}}

形式语法

{{CSSSyntax}}

示例

竖排文本的边框颜色

HTML

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

CSS

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

.exampleText {
  writing-mode: vertical-lr;
  border: 10px solid blue;
  border-block-start-color: red;
}

结果

{{EmbedLiveSample("竖排文本的边框颜色", 140, 140)}}