JAVASCRIPT

addeve

document.querySelector('.check').addEventListener('click', function () {
  const guess = Number(document.querySelector('.guess').value);
  console.log(guess, typeof guess);

})

addeve

 <section class="left">
        <input type="number" class="guess" />
        <button class="btn check">Check!</button>
      </section>

addeve

.guess {
  background: none;
  border: 4px solid #eee;
  font-family: inherit;
  color: inherit;
  font-size: 5rem;
  padding: 2.5rem;
  width: 25rem;
  text-align: center;
  display: block;
  margin-bottom: 3rem;
}
.btn {
  border: none;
  background-color: #eee;
  color: #222;
  font-size: 2rem;
  font-family: inherit;
  padding: 2rem 3rem;
  cursor: pointer;
}