利用伪元素:after绘制水波纹，此处的水波纹效果使用了css函数radial-gradient(径向渐变)，再配合3D缩放transform及transition过渡效果实现水波动态效果。
以下代码使用less语言
.button-ripple {
overflow: hidden;
position: relative;
transition: background-color 0.3s linear, border 0.3s linear;
&:after {
content: "";
display: block;
position: absolute;
width: 100%;
height: 100%;
top: 0;
left: 0;
pointer-events: none;
background-image: radial-gradient(
circle,
#000 10%,
rgba(0, 0, 0, 0) 10.01%
);
background-repeat: no-repeat;
background-position: 50%;
transform: scale(10);
opacity: 0;
transition: transform 0.5s, opacity 1s;
}
&:active:after {
transform: scale(0);
opacity: 0.2;
transition: 0s;
}
}
