<gradient>

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

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

<gradient> CSS 数据类型是 <image> 的一种特殊类型，包含两种或多种颜色的过渡转变。

尝试一下

background: linear-gradient(#f69d3c, #3f87a6);

background: radial-gradient(#f69d3c, #3f87a6);

background: repeating-linear-gradient(#f69d3c, #3f87a6 50px);

background: repeating-radial-gradient(#f69d3c, #3f87a6 50px);

background: conic-gradient(#f69d3c, #3f87a6);

<section class="display-block" id="default-example">
  <div id="example-element"></div>
</section>

#example-element {
  min-height: 100%;
}

CSS 渐变没有内在尺寸，也就是说，它没有固有或首选的尺寸，也没有首选的比例，其实际大小取决于所应用的元素的大小。

语法

<gradient> 数据类型是由下面列出的函数类型中的一个定义的。

线性渐变

线性渐变会在一个假想的直线上过渡颜色。线性渐变是由 linear-gradient() 函数产生的。

径向渐变

径向渐变从一个中间点（原点）开始过渡颜色。径向渐变是由 radial-gradient() 函数产生的。

重复渐变

重复渐变可根据需要复制渐变，以填充指定区域。重复渐变是使用 repeating-linear-gradient() 和 repeating-radial-gradient() 函数生成的。

锥形渐变

锥形渐变会沿着一个圆过渡颜色。锥形渐变是由 conic-gradient() 函数产生的。

插值

就像很多包含颜色的插值一样，渐变是在 alpha 预乘的颜色空间中插值的。这会避免在颜色和不透明度都在改变时出现未预料的灰色阴影。（注意旧的浏览器可能在使用 transparent 关键字时不使用此行为。）

形式语法

<gradient> = 
  <linear-gradient()>            |
  <repeating-linear-gradient()>  |
  <radial-gradient()>            |
  <repeating-radial-gradient()>  

<linear-gradient()> = 
  linear-gradient( [ <linear-gradient-syntax> ] )  

<repeating-linear-gradient()> = 
  repeating-linear-gradient( [ <linear-gradient-syntax> ] )  

<radial-gradient()> = 
  radial-gradient( [ <radial-gradient-syntax> ] )  

<repeating-radial-gradient()> = 
  repeating-radial-gradient( [ <radial-gradient-syntax> ] )  

<linear-gradient-syntax> = 
  [ <angle> | <zero> | to <side-or-corner> ]? , <color-stop-list>  

<radial-gradient-syntax> = 
  [ <radial-shape> || <radial-size> ]? [ at <position> ]? , <color-stop-list>  

<side-or-corner> = 
  [ left | right ]  ||
  [ top | bottom ]  

<color-stop-list> = 
  <linear-color-stop> , [ <linear-color-hint>? , <linear-color-stop> ]#?  

<radial-shape> = 
  circle   |
  ellipse  

<radial-size> = 
  <radial-extent>               |
  <length [0,∞]>                |
  <length-percentage [0,∞]>{2}  

<position> = 
  [ left | center | right | top | bottom | <length-percentage> ]  |
  [ left | center | right ] && [ top | center | bottom ]  |
  [ left | center | right | <length-percentage> ] [ top | center | bottom | <length-percentage> ]  |
  [ [ left | right ] <length-percentage> ] && [ [ top | bottom ] <length-percentage> ]  

<linear-color-stop> = 
  <color> <length-percentage>?  

<linear-color-hint> = 
  <length-percentage>  

<radial-extent> = 
  closest-corner   |
  closest-side     |
  farthest-corner  |
  farthest-side    

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

示例

线性渐变示例

简单的线性渐变示例。

<div class="linear-gradient">线性渐变</div>

div {
  width: 240px;
  height: 80px;
}

css

.linear-gradient {
  background: linear-gradient(
    to right,
    red,
    orange,
    yellow,
    green,
    blue,
    indigo,
    violet
  );
}

径向渐变示例

简单的径向渐变。

<div class="radial-gradient">径向渐变</div>

div {
  width: 240px;
  height: 80px;
}

css

.radial-gradient {
  background: radial-gradient(red, yellow, rgb(30, 144, 255));
}

重复渐变示例

简单的重复线性和径向渐变示例。

<div class="linear-repeat">重复的线性渐变</div>
<br />
<div class="radial-repeat">重复的径向渐变</div>

div {
  width: 240px;
  height: 80px;
}

css

.linear-repeat {
  background: repeating-linear-gradient(
    to top left,
    lightpink,
    lightpink 5px,
    white 5px,
    white 10px
  );
}

.radial-repeat {
  background: repeating-radial-gradient(
    powderblue,
    powderblue 8px,
    white 8px,
    white 16px
  );
}

锥形渐变示例

简单的锥形渐变示例。注意这目前并非在浏览器中广泛支持。

<div class="conic-gradient">锥形渐变</div>

div {
  width: 200px;
  height: 200px;
}

css

.conic-gradient {
  background: conic-gradient(lightpink, white, powderblue);
}

规范

Specification
CSS Images Module Level 4 # gradients