<div class="container">

  <h2>Verify Your Account</h2>

  <p>We emailed you the six digit code to cool_guy@email.com<br />Enter the code below to confirm your email address.</p>

  <div class="code-container">

     <input type="number" class="code" placeholder="0" min="0" max="9" required>

     <input type="number" class="code" placeholder="0" min="0" max="9" required>

     <input type="number" class="code" placeholder="0" min="0" max="9" required>

     <input type="number" class="code" placeholder="0" min="0" max="9" required>

     <input type="number" class="code" placeholder="0" min="0" max="9" required>

     <input type="number" class="code" placeholder="0" min="0" max="9" required>

  </div>

  <small class="info">THis is design only. We didn't actually send you an email as we don't have your email, right?</small>
</div>

let codes = document.querySelectorAll('.code')

codes[0].focus()

codes.forEach((code,idx) => {

    code.addEventListener('keydown', (e) =>{

        if(e.key >= 0 && e.key <=9) {

            codes[idx].value = ''

            setTimeout(() => codes[idx + 1].focus(), 10)

        }else if (e.key === 'Backspace') {

            setTimeout(() => codes[idx - 1].focus(), 10)

        }

    })

})

@import url('https://fonts.googleapis.com/css?family=Muli:300,700&display=swap');

*{

    box-sizing: border-box;

}

body{

    background: #fbfcfe;

    font-family: "Muli", sans-serif;

    display: flex;

    align-items: center;

    justify-content: center;

    height: 100vh;

    overflow: hidden;

    margin: 0;

}

.container{

    padding: 30px;

    background: #fff;

    border: 3px solid #000;

    border-radius: 10px;

    max-width: 1000px;

    text-align: center;

}

.code-container{

    display: flex;

    align-items: center;

    justify-content: center;

    margin: 40px 0;

}

.code{

    border-radius: 5px;

    font-size: 75px;

    height: 120px;

    width: 100px;

    border: 1px solid #eee;

    margin: 1%;

    text-align: center;

    font-weight: 300;

    -moz-appearance: textfield;

}

.code::-webkit-outer-spin-button,

.code::-webkit-inner-spin-button{

    -webkit-appearance: none;

    margin: 0;

}

.code:valid{

    border: #3498bd;

    box-shadow: 0 10px 10px -5px rgba(0, 0, 0, 0.25);

}

.info{

    background: #eaeaea;

    display: inline-block;

    padding: 10px;

    line-height: 20px;

    max-width: 400px;

    color: #777;

    border-radius: 5px;

}

@media(max-width:600px){

    .code-container{

        flex-wrap: wrap;

    }

    .code{

        font-size: 60px;

        height: 80px;

        max-width: 70px;

    }

}