这两个0是 左右 上下。用px调整。如果是0就是居中。
15px是你要光圈。越大就范围就越广。类似于病毒扩散那种感觉.padding可无视，是为了放你class一个span或button自己就撑开了
一个使用伪元素来实现边框逐渐发光的代码，主要用到scale和opacity这两个属性。Html代码
<div>
<img src="http://tva2.sinaimg.cn/crop.0.0.180.180.180/6830a53bjw8f2qo4xzc2zj20500500t0.jpg"/>
<div>
<p>CSS3 逐渐发光的方格边框</p>
<p>CSS3 逐渐发光的方格边框</p>
</div>
</div>
Css代码
.light{
background: #fff
width: 180px
height: 180px
margin: 100px auto
position: relative
text-align: center
color: #333
transform:translate3d(0,0,0)
}
.light-inner{
padding: 60px 30px 0
pointer-events: none
position: absolute
left: 0
top: 0
bottom: 0
right: 0
text-align: center
transition: background 0.35s
backface-visibility: hidden
}
.light-inner:before, .light-inner:after{
display: block
content: ""
position: absolute
left: 30px
top: 30px
right: 30px
bottom: 30px
border: 1px solid #fff
opacity: 0
transition: opacity 0.35s, transform 0.35s
}
.light-inner:before{
border-left: 0
border-right: 0
transform:scaleX(0,1)
}
.light-inner:after{
border-top: 0
border-bottom: 0
transform: scaleY(1,0)
}
.light:hover .light-inner{
background: #458fd2
}
.light:hover .light-inner:before, .light:hover .light-inner:after{
opacity: 1
transform: scale3d(1,1,1)
}
.light-inner p{
transition: opacity .35s, transform 0.35s
transform: translate3d(0,20px,0)
color: #fff
opacity: 0
line-height: 30px
}
.light:hover .light-inner p{
transform: translate3d(0,0,0)
opacity: 1
}
div{width: 200pxheight: 200pxbackground: #dadadaborder:5px solid redanimation: shine 1s alternate infinite}@keyframes shine{
from{border-color: rgba(0,0,0,0)}
to{border-color: rgba(0,0,0,1)}
}
