CSS3背景渐变无法验证,有人可以告诉我为什么？内部代码示例

Question

有人能告诉我为什么以下的CSS没有验证？我一直在努力研究这个,没有运气.我读过的所有文档都说这是为什么在css3中做渐变的正确方法.

#header {
  color: white;
  font-size: 12px;
  font-family: Helvetica, Verdana, Arial, sans-serif;
  background: black;
  background: -moz-linear-gradient(top,  rgba(0,0,0,0.65) 0%, rgba(0,0,0,0) 100%);
  background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(0,0,0,0.65)), color-stop(100%,rgba(0,0,0,0)));
  background: -webkit-linear-gradient(top,  rgba(0,0,0,0.65) 0%,rgba(0,0,0,0) 100%);
  background: -o-linear-gradient(top,  rgba(0,0,0,0.65) 0%,rgba(0,0,0,0) 100%);
  background: -ms-linear-gradient(top,  rgba(0,0,0,0.65) 0%,rgba(0,0,0,0) 100%);
  background: linear-gradient(top,  rgba(0,0,0,0.65) 0%,rgba(0,0,0,0) 100%);
  width: 100%;
  height: 35px;
  margin-top: 0px;
  margin-left: auto;
  margin-right: auto;
  padding: 10px;
  position: fixed;
  top: 0px;
  z-index: 1000;
}

这些是我得到的验证错误:

TextArea的W3C CSS Validator结果(CSS级别3)

抱歉! 我们发现了以下错误(6)

URI:TextArea

6 #header值错误:background-color -moz-linear-gradient(top,rgba(0,0,0,0.65)0%,rgba(0,0,0,0)100%)不是背景色值:-moz-linear-gradient(top,rgba(0,0,0,0.65)0%,rgba(0,0,0,0)100%)

7 #header值错误:background-color -webkit-gradient(线性,左上,左下,颜色停止(0%,rgba(0,0,0,0.65)),颜色停止(100%,rgba( 0,0,0,0)))不是背景颜色值:-webkit-gradient(线性,左上,左下,颜色停止(0%,rgba(0,0,0,0.65)),颜色停止(100%,rgba(0,0,0,0)))

8 #header值错误:background-color -webkit-linear-gradient(top,rgba(0,0,0,0.65)0%,rgba(0,0,0,0)100%)不是背景色值:-webkit-linear-gradient(top,rgba(0,0,0,0.65)0%,rgba(0,0,0,0)100%)

9 #header值错误:background-color -o-linear-gradient(顶部,rgba(0,0,0,0.65)0%,rgba(0,0,0,0)100%)不是背景颜色值:-o-linear-gradient(top,rgba(0,0,0,0.65)0%,rgba(0,0,0,0)100%)

10 #header值错误:background-color -ms-linear-gradient(顶部,rgba(0,0,0,0.65)0%,rgba(0,0,0,0)100%)不是背景颜色值:-ms-线性渐变(顶部,rgba(0,0,0,0.65)0%,rgba(0,0,0,0)100%)

11 #header值错误:背景色线性渐变(顶部,rgba(0,0,0,0.65)0%,rgba(0,0,0,0)100%)不是背景颜色值:线性-gradient(top,rgba(0,0,0,0.65)0%,rgba(0,0,0,0)100%)