css 颜色渐变

.top_nav {

    width: 100%;

    height: 29px;

      

    /* 如果浏览器不支持渐变，使用图像作为背景 */

    background: url(gradient.jpg);

      

    /* Webkit: Safari 4-5, Chrome 1-9 */

    background: -webkit-gradient(linear, 0% 0%, 0% 100%, from(#636363), to(#393939));

      

    /* Webkit: Safari 5.1+, Chrome 10+ */

    background: -webkit-linear-gradient(top, #636363, #393939);

      

    /* Firefox 3.6+ */

    background: -moz-linear-gradient(top, #636363, #393939);

      

    /* Opera 11.10+ */

    background: -o-linear-gradient(top, #636363, #393939);

      

    /* IE 10 */

    background: -ms-linear-gradient(top, #636363, #393939);

      

    /* IE < 10 */

    FILTER: progid:DXImageTransform.Microsoft.Gradient(startColorStr=#636363, endColorStr=#393939);

      

    // CSS3 标准

    background: linear-gradient(#636363, #393939);

}