Un floating label en pur css ! \o/ Merci Timo !

<label>

    <input type="text" id="name" placeholder=" ">

    <span>Name</span>

</label>

<label>

    <input type="password" id="password" placeholder=" ">

    <span>Password</span>

</label>

 label {

  position: relative;

}



input {

    padding: 10px;

    border: 1px silver solid;

}

span {

  position: absolute;

  transition: all 200ms;

  opacity: 0.5;

  left: 0px;

  padding: 10px;

  transform-origin: top left;

}



input:not(:placeholder-shown) + span {

  transform: translateY(-100%) scale(.75);

  opacity: 1;

  padding: 0 10px;

}