CSS 属性 inset-block 定义了元素的逻辑块首和块末偏移，并根据元素的书写模式、行内方向和文本朝向对应至实体偏移。根据 {{CSSXref("writing-mode")}}、{{CSSXref("direction")}} 和 {{CSSXref("text-orientation")}} 所定义的值，此属性对应于 {{CSSXref("top")}} 和 {{CSSXref("bottom")}}，或者 {{CSSXref("right")}} 和 {{CSSXref("left")}} 属性。

{{InteractiveExample("CSS Demo: inset-block")}}

```css interactive-example-choice inset-block: 10px 20px; writing-mode: horizontal-tb;


```css interactive-example-choice
inset-block: 20px 40px;
writing-mode: vertical-rl;

```css interactive-example-choice inset-block: 5% 20%; writing-mode: horizontal-tb;


```css interactive-example-choice
inset-block: 1rem auto;
writing-mode: vertical-lr;

```html interactive-example

I am absolutely positioned.

As much mud in the streets as if the waters had but newly retired from the face of the earth, and it would not be wonderful to meet a Megalosaurus, forty feet long or so, waddling like an elephantine lizard up Holborn Hill. 


```css interactive-example
.example-container {
  border: 0.75em solid #ad1457;
  padding: 0.75em;
  text-align: left;
  position: relative;
  width: 100%;
  min-height: 200px;
}

#example-element {
  background-color: #07136c;
  border: 6px solid #ffa000;
  color: white;
  position: absolute;
  inset: 0;
}

属性构成

此属性为下列 CSS 属性的简写属性：

  • {{CSSXref("inset-block-end")}}
  • {{CSSXref("inset-block-start")}}

语法

/* 长度值 */
inset-block: 3px 10px;
inset-block: 2.4em 3em;
inset-block: 10px; /* 应用于块首和块末 */

/* 包含块的宽度或高度的百分比 */
inset-block: 10% 5%;

/* 关键词值 */
inset-block: auto;

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

取值

inset-block 属性的取值与 {{CSSXref("left")}} 属性相同。

形式定义

{{CSSInfo}}

形式语法

{{CSSSyntax}}

示例

设置块首和块末偏移

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;
  position: relative;
  inset-block: 20px 50px;
  background-color: #c8c800;
}

结果

{{EmbedLiveSample("设置块首和块末偏移", 140, 140)}}