body{
    margin: 0;
    padding: 0;
    font-family: sans-serif;
        
    
}
.box{
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
    width: 400px;
    padding: 40px;
    background: rgba(0,0,0,.8);
    box-sizing: border-box;
    box-shadow: 0 15px 25px rgba(0,0,0,.5);
    border-radius: 10px;
}
.box h2{
    margin: 0 0 30px;
    padding: 0;
    color: white;
    text-align: center;
}
.box .inputBox{
    position: relative;    
}
.box .inputBox input{
    width: 100%;
    padding: 10px;
    font-size: 16px;
    color: white;
    margin-bottom: 30px;
    border: none;
    border-bottom:1px solid white;
    outline: none;
    background: transparent;
}
.box .inputBox label{
    position: absolute;
    top: 0;
    left: 0;
    padding: 10px;
    font-size: 16px;
    color: white;
    pointer-events: none;
    transition: .3s;    
}
.box .inputBox input:focus ~ label, .box .inputBox input:valid ~ label{
    top: -18px;
    font-size: 12px;
    color:#43a4f9;
}
.box .inputBox input:focus {
    border-bottom:2px solid #43a4f9;
}