我同意szajmon的观点。他和昆汀回答的唯一问题是跨浏览器兼容性。

HTML:

<div class="g">
    <div>bla</div>
</div>

CSS:

.g {
background-image: -webkit-linear-gradient(300deg, white, black, white); /* webkit browsers (Chrome & Safari) */
background-image: -moz-linear-gradient(300deg, white, black, white); /* Mozilla browsers (Firefox) */
filter: progid:DXImageTransform.Microsoft.gradient(startColorstr='#ffffff', endColorstr='#000000', gradientType='1'); /* Internet Explorer */
background-image: -o-linear-gradient(300deg,rgb(255,255,255),rgb(0,0,0) 50%,rgb(255,255,255) 100%); /* Opera */
}

.g > div { background: #fff; }

试试这段代码

.gradientBoxesWithOuterShadows { 
height: 200px;
width: 400px; 
padding: 20px;
background-color: white; 

/* outer shadows  (note the rgba is red, green, blue, alpha) */
-webkit-box-shadow: 0px 0px 12px rgba(0, 0, 0, 0.4); 
-moz-box-shadow: 0px 1px 6px rgba(23, 69, 88, .5);

/* rounded corners */
-webkit-border-radius: 12px;
-moz-border-radius: 7px; 
border-radius: 7px;

/* gradients */
background: -webkit-gradient(linear, left top, left bottom, 
color-stop(0%, white), color-stop(15%, white), color-stop(100%, #D7E9F5)); 
background: -moz-linear-gradient(top, white 0%, white 55%, #D5E4F3 130%); 
}

或者可以参考这个小提琴:http://jsfiddle.net/necolas/vqnk9/

这是一个hack，但是在某些情况下你可以通过使用background-image来指定渐变，然后用box-shadow掩盖实际的背景来达到这种效果。例如:

p {
  display: inline-block;
  width: 50px;
  height: 50px;
  /* The background is used to specify the border background */
  background: -moz-linear-gradient(45deg, #f00, #ff0);
  background: -webkit-linear-gradient(45deg, #f00, #ff0);
  /* Background origin is the padding box by default.
  Override to make the background cover the border as well. */
  -moz-background-origin: border;
  background-origin: border-box;
  /* A transparent border determines the width */
  border: 4px solid transparent;
  border-radius: 8px;
  box-shadow:
    inset 0 0 12px #0cc, /* Inset shadow */
    0 0 12px #0cc, /* Outset shadow */
    inset -999px 0 0 #fff; /* The background color */
}

来自:http://blog.nateps.com/the-elusive-css-border-gradient

Mozilla目前只支持CSS渐变作为background-image属性的值，以及在简写背景中。

——https://developer.mozilla.org/en/CSS/-moz-linear-gradient

Example 3 - Gradient Borders

border: 8px solid #000;
-moz-border-bottom-colors: #555 #666 #777 #888 #999 #aaa #bbb #ccc;
-moz-border-top-colors: #555 #666 #777 #888 #999 #aaa #bbb #ccc;
-moz-border-left-colors: #555 #666 #777 #888 #999 #aaa #bbb #ccc;
-moz-border-right-colors: #555 #666 #777 #888 #999 #aaa #bbb #ccc;
padding: 5px 5px 5px 15px; 

——http://www.cssportal.com/css3-preview/borders.htm

试试这个，对我很管用。

div { border - radius: 20 px; 身高:70 vh; 溢出:隐藏; ｝ {前div:: 内容:”; 显示:块; box-sizing: border-box; 高度:100%; 边框:1em实心透明; 边界图像:线性渐变(到顶部，红色0%，蓝色100%); border-image-slice: 1; ｝ < div > < / div >

这是小提琴的链接 https://jsfiddle.net/yash009/kayjqve3/1/希望这对你有所帮助

渐变边框的例子

使用border-image css属性

credit to: border-image

.grad-border { 身高:1 px; 宽度:85%; 保证金:0自动; 显示:flex; ｝ .left-border， .right-border { 宽度:50%; Border-bottom: 2px solid #695f52; 显示:inline-block; ｝ .left-border { Border-image:线性梯度(270deg， #b3b3b3， #fff) 1; ｝ .right-border { 边界图像:线性梯度(90度，#b3b3b3， #fff) 1; ｝ < div class = " grad-border”> < div class = "左边框" > < / div > < div class = "右边界" > < / div > < / div >