HTMLify

@import url('https://fonts.googleapis.com/css2?family=Nunito&display=swap');
*{
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}
html{
  font-size: 10px;
  font-family: 'Nunito', sans-serif;
}
body{
  background-color: rgb(28, 27, 34);
  color: white;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
}
section{
  width: 100%;
}
.container{
  width: 90%;
  max-width: 450px;
  margin: 0 auto;
}
form,.number-fact{
  width: 100%;
  background-color: rgb(42, 41, 42);
  padding: 20px;
  border-radius: 8px;
}
input[type="number"]{
  width: 70%;
  height: 40px;
  border-radius: 4px;
  outline: none;
  border: none;
  background-color: #3a3a3b;
  font-size: 24px;
  color: aliceblue;
  padding-left: 10px;
}
input[type="number"]::placeholder{
  font-size: 24px;
  font-family: "Nunito";
  font-weight: 400;
}
button{
  display: inline-block;
  width: 25%;
  font-size: 24px;
  height: 40px;
  background-color:#3a3a3b;
  color: aliceblue;
  border: none;
  outline: none;
  cursor: pointer;
  margin-left: 10px;
  border-radius: 4px;
}
.number-fact{
  margin-top: 20px;
  height: auto;
  font-size: 20px;
}
@media only screen and (max-width: 678px){
  form button{
    font-size: 18px;
  }
}