body,
input {
  width: 100%;
  text-align: center;
}
body {
  font-family: Arial, sans-serif;
  background-color: #121212;
  color: #338ef7;
  font-size: 1.5rem;
  margin: 10% auto;
}
form {
  max-width: 350px;
  margin: 0 auto;
}
input,
label {
  margin: 10px 0;
  color: #338ef7;
  font-size: 2rem;
}
input {
  padding: 10px;
  border: 1px solid #338ef7;
  border-radius: 5px;
  background-color: #333;
  box-sizing: border-box;
}
button {
  background-color: #338ef7;
  color: #efefef;
  border: none;
  margin-top: 15px;
  padding: 10px 20px;
  border-radius: 5px;
  cursor: pointer;
  font-size: 1rem;
  font-weight: 700;
}
input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}
input[type='number'] {
  -moz-appearance: textfield;
}