<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <meta name="viewport" content="width=device-width, initial-scale=1.0">

    <title>Document</title>

    <style>

        html {

  height: 100%;

}

body {

  margin:0;

  padding:0;

  font-family: sans-serif;

  background: linear-gradient(#141e30, #243b55);

}


.contact-form-box {

  position: absolute;

  top: 50%;

  left: 50%;

  width: 400px;

  padding: 40px;

  transform: translate(-50%, -50%);

  background: rgba(0,0,0,.5);

  box-sizing: border-box;

  box-shadow: 0 15px 25px rgba(0,0,0,.6);

  border-radius: 10px;

}



.contact-form-box .user-box {

  position: relative;

}


.contact-form-box .user-box input {

  width: 100%;

  padding: 10px 0;

  font-size: 16px;

  color: #fff;

  margin-bottom: 30px;

  border: none;

  border-bottom: 1px solid #fff;

  outline: none;

  background: transparent;

}

.contact-form-box .user-box label {

  position: absolute;

  top:0;

  left: 0;

  padding: 10px 0;

  font-size: 16px;

  color: #fff;

  pointer-events: none;

  transition: .5s;

}


.contact-form-box .user-box input:focus ~ label,

.contact-form-box .user-box input:valid ~ label {

  top: -20px;

  left: 0;

  color: #03e9f4;

  font-size: 12px;

}


    </style>

</head>

<body>

    <div class="contact-form-box">

 

  <form>

    <div class="user-box">

      <input type="text" name="" required="">

      <label>Username</label>

    </div>

    <div class="user-box">

      <input type="password" name="" required="">

      <label>Password</label>

    </div>

   

  </form>

</div>

</body>

</html>