<div class="container">
  <h3 class="title">OTP Verification</h3>
  <p class="sub-title">
    Enter the OTP you received to
    <span class="phone-number">sittisak@hotmail.com</span>
  </p>
  <div class="wrapper">
    <input type="text" class="field 1" maxlength="1">
    <input type="text" class="field 2" maxlength="1">
    <input type="text" class="field 3" maxlength="1">
    <input type="text" class="field 4" maxlength="1">
  </div>
  <button class="resend">
    Resend OTP
    <i class="fa fa-caret-right"></i>
  </button>
</div>

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: 'Poppins', sans-serif;
}

html,
body {
  height: 100%;
  display: grid;
  place-items: center;
  background-color: #EAF5F6;
}

.container {
  width: 400px;
  padding: 50px;
  background-color: #ffffff;
  border-radius: 25px;
}

h3.title {
  font-size: 28px;
  font-weight: 700;
  color: #093030;
  margin-bottom: 25px;
}

p.sub-title {
  color: #B5BAB8;
  font-size: 14px;
  margin-bottom: 25px;
}

p span.phone-number {
  display: block;
  color: #093030;
  font-weight: 600;
}

.wrapper {
  width: 100%;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  justify-items: space-between;
}

.wrapper input.field {
  width: 50px;
  line-height: 75px;
  font-size: 32px;
  border: none;
  background-color: #EAF5F6;
  border-radius: 5px;
  text-align: center;
  text-transform: uppercase;
  color: #093030;
  margin-bottom: 25px;
}

.wrapper input.field:focus {
  outline: none;
}

button.resend {
  background-color: transparent;
  border: none;
  font-weight: 600;
  color: #3DAFE1;
  cursor: pointer;
}

button.resend i {
  margin-left: 5px;
}

const inputFields = document.querySelectorAll("input.field");

inputFields.forEach((field) => {
  field.addEventListener("input", handleInput);
});

function handleInput(e) {
  let inputField = e.target;
  if (inputField.value.length >= 1) {
    let nextField = inputField.nextElementSibling;
    return nextField && nextField.focus();
  }
}