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Box Shadow 盒子阴影

盒子阴影

box-shadow属性在元素的框架周围附加一个或多个阴影（可以在内部）。它是一个选项，让您有能力轻松设计精彩的阴影效果。框阴影是提升网页视觉效果的绝佳方式。

可以用几个属性描述盒子阴影，包括：

  • X和Y偏离元素
  • 模糊和传播半径
  • 颜色

句法：

  div { 
    box-shadow: none | [inset? && [ <offset-x> <offset-y> <blur-radius>? <spread-radius>? <color>? ] ]# 
    }

  • inset (default: none)

If not specified, the shadow is assumed to be a drop shadow (as if the box were raised above the content). The presence of the inset keyword changes the shadow to one inside the frame

  • offset-x offset-y

These are two length values to set the shadow offset. specifies the horizontal distance. Negative values place the shadow to the left of the element. offset-y specifies the vertical distance. Negative values place the shadow above the element. See length for possible units.

  • blur-radius (default: 0)

This is a third length value. The larger this value, the bigger the blur, so the shadow becomes bigger and lighter. Negative values are not allowed. If not specified, it will be 0 (the shadow's edge is sharp).

  • spread-radius (default: 0)

This is a fourth value. Positive values will cause the shadow to expand and grow bigger, negative values will cause the shadow to shrink. If not specified, it will be 0 (the shadow will be the same size as the element).

  • color

This value is used to set the color of the shadow, usually defined with hex #000000, rgba value rgba(55,89,88,0.8) or rgb value rgb(55,89,88)

Extended

To maximize compatibility, it is recommended that you declare box shadow property for moz-appearance and webkit, this extends the normal syntax to:


CSS DIV { box-shadow：none | \[插图？ && \[ ？ ？ ？ \]\]＃ -moz-box-shadow：无| \[插图？ && \[ ？ ？ ？ \]\]＃ -webkit-box-shadow：none | \[插图？ && \[ ？ ？ ？ \]\]＃ }

However, this step can be ignored if it is creating confusion, as moz property and webkit property will only work in specific applications such as Firefox, and are not on a standards track.

Examples

Basic use


CSS div { 宽度：200px; 身高：50px; 背景色：＃333; box-shadow：10px 10px 5px #ccc; }

10px - offset-x 10px - offset-y 5px - blur #ccc - light gray color

It will display

image

Inside box shadow


CSS div { 宽度：200px; 身高：50px; 背景色：＃333; box-shadow：inset 10px 10px 5px #ccc; }

It uses very similar code, but with inset value, which displays shadow inside the div element

image

Multiple box shadows


CSS div { 宽度：200px; 身高：50px; 背景色：＃333; box-shadow：inset 10px 10px 5px #ccc，10px 10px 5px #ccc; } \`\`\`

您可以使用逗号组合前两个框阴影，以在同一个div上获得多个框阴影

#### 更多信息

*   文件： [MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/box-shadow)