整理文档，搜刮出一个css3实现wifi信号逐渐增强效果实例的代码，稍微整理精简一下做下分享。

效果图

下面是实现代码：

wifi信号

*{

margin: 0;

padding: 0;

}

.box {

width: 240px;

height: 240px;

box-sizing: border-box;

position: relative;

margin: 100px auto;

}

.wifi-symbol {

width: 200px;

height: 200px;

margin-left: 18px;

box-sizing: border-box;

overflow: hidden;

transform: rotate(45deg);

}

.wifi-circle {

border: 10px solid #ccc;

border-radius: 50%;

position: absolute;

}

.first {

width: 260px;

height: 260px;

top: 0;

left: 0;

animation: run1 4s linear infinite;

}

@keyframes run1 {

0% {

border-color: #ccc;

}

25% {

border-color: #ccc;

}

50% {

border-color: #ccc;

}

75% {

border-color: #ccc;

}

100% {

border-color: #97a8e6;

}

}

.second {

width: 200px;

height: 200px;

top: 60px;

left: 60px;

animation: run2 4s linear infinite;

}

@keyframes run2 {

0% {

border-color: #ccc;

}

25% {

border-color: #ccc;

}

50% {

border-color: #ccc;

}

75% {

border-color: #97a8e6;

}

100% {

border-color: #ccc;

}

}

.third {

width: 140px;

height: 140px;

top: 120px;

left: 120px;

animation: run3 4s linear infinite;

}

@keyframes run3 {

0% {

border-color: #ccc;

}

25% {

border-color: #ccc;

}

50% {

border-color: #97a8e6;

}

75% {

border-color: #ccc;

}

100% {

border-color: #ccc;

}

}

.fourth {

width: 20px;

height: 20px;

background: #ccc;

top: 180px;

left: 180px;

animation: run4 4s linear infinite;

}

@keyframes run4 {

0% {

background: #ccc;

border-color: #ccc;

}

25% {

background: #97a8e6;

border-color: #97a8e6;

}

50% {

background: #ccc;

border-color: #ccc;

}

75% {

background: #ccc;

border-color: #ccc;

}

100% {

background: #ccc;

border-color: #ccc;

}

}