我发现最好的方法是使用伪元素并在其上应用模糊的边界。
.border-shadow {
position: relative;
display: inline-block;
border: 3px solid #F01476;
padding: 20px;
background-color: transparent;
&:after {
content: '';
position: absolute;
top: 0;
right: 0;
bottom: 0;
left: 0;
outline: 3px solid #F01476;
filter: blur(2px);
transform: translateY(5px);
}
}
如果需要边界渐变,可以执行以下操作:
.border-shadow {
position: relative;
display: inline-block;
padding: 20px;
background-color: transparent;
&:after {
content: '';
position: absolute;
top: -3px;
right: -3px;
bottom: -3px;
left: -3px;
filter: blur(2px);
transform: translateY(5px);
}
&, &:after {
border-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='50' height='50'><defs><linearGradient id='redgradient'><stop offset='0' stop-color='%23F01476'/><stop offset='1' stop-color='%23F3590F'/></linearGradient></defs><g id='Layer_1'><path d='M0,0 L50,0 L50,50 L0,50 L0,0 z' fill='url(%23redgradient)' width='100%' height='100%'/></g></svg>") 10% stretch;
}
}
See the jsfiddle for both examples in action
autoprefixer