css3 如何实现圆边框的渐变? 如图
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<style>
div { width:100px; height:100px; -webkit-transform:rotate(90deg);}
div:before {content:""; display:block; width:100px;height:50px; margin-top:10px; padding:10px; padding-bottom:0; box-sizing:border-box;
border-top-left-radius:50px;
border-top-right-radius:50px;
background:-webkit-gradient(
linear,
left top,
right top,
color-stop(0,#fff),
color-stop(1,#fff)
),-webkit-gradient(
linear,
left top,
right top,
color-stop(0,#077df8),
color-stop(1,#74baff)
);
background-clip:content-box,padding-box;
}
div:after {content:""; display:block; width:100px;height:50px; padding:10px; padding-top:0; box-sizing:border-box;
border-bottom-left-radius:50px;
border-bottom-right-radius:50px;
background:-webkit-gradient(
linear,
left top,
right top,
color-stop(0,#fff)
