实现效果：
当鼠标点击按钮时：
实现代码：
<!DOCTYPE html>
<html><head><meta charset="utf-8"><title></title><style>div{margin-top: 20px;margin-left: 20px;}.button{border: solid 4px transparent;border-image: linear-gradient(to right, aqua,transparent);border-image-slice: 1;}.button:active{color: white;background-image: linear-gradient(to right, aqua, transparent);border: none;}.button-3D{position: relative;background-color: aqua;color: white;padding: 15px 20px;font-size: 1.5fr;box-shadow: -6px 6px 0 lightblue;}.button-3D:active {background: hsl(77, 100%, 40%);top: 3px;left: -3px;box-shadow: -3px 3px 0 hsl(80, 100%, 30%);}</style></head><body><div id="button1"><button class="button">不要点我!(◔◡◔)</button></div><div id="button2"><button class="button-3D">不要点我!(◔◡◔)</button></div></body>
</html>
