边框渐变

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>border渐变</title>
    <style>
     button{
        background:transparent;
        color:#23b7cb;
        font-size:15px;
        padding:5px 15px;
        border:1px transparent solid;
        border-image:linear-gradient(to right,#000718,#23b7cb) 1 10;
     }
      
    </style>
</head>
<body>
    <button>进入平台</button>
</body>
</html>