<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<style type="text/css">
body{
display: flex;
flex-direction: column;
justify-content: center;
align-items: center;
background: #000;
min-height: 100vh;
}
a{
position: relative;
padding: 10px 30px;
margin: 45px 0;
color:#21ebff;
text-decoration: none;
font-size: 20px;
text-transform: uppercase;
transition: 0.2s;
overflow: hidden;
cursor: pointer;
}
a:hover{
background: #21EBFF;
color: #111;
box-shadow: 0 0 50px #21EBFF;
transition-delay: 0.2s;
-webkit-box-reflect: below 1px linear-gradient(transparent,#0003);
}
a::before{
content: '';
position: absolute;
top:0;
left:0;
width: 10px;
height: 10px;
border-top:2px solid #21EBFF;
border-left:2px solid #21EBFF;
transition: 0.2s;
transition-delay: 0.2s;
}
a:hover::before,a:hover::after{
width: 100%;
height:100%;
transition-delay: 0s;
}
a::after{
content: '';
position: absolute;
bottom:0;
right:0;
width: 10px;
height: 10px;
border-bottom:2px solid #21EBFF;
border-right:2px solid #21EBFF;
transition: 0.2s;
transition-delay: 0.2s;
}
a:nth-child(1){
filter: hue-rotate(115deg);
}
a:nth-child(3){
filter: hue-rotate(270deg);
}
</style>
<body>
<a > BUTTON </a>
<a > BUTTON </a>
<a > BUTTON </a>
</body>
</html>
