body {
  font-family: 'Courier New', monospace;
  background-color: #f0f0f0;
  color: #000;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}
.container {
  background: #fff;
  padding: 20px 30px;
  border: 2px solid #000;
  box-shadow: 5px 5px #ccc;
  text-align: center;
}
input {
  font-family: inherit;
  padding: 5px;
  margin: 5px 0 15px 0;
  width: 80%;
  font-size: 16px;
}
button {
  font-family: inherit;
  font-size: 16px;
  padding: 5px 20px;
  cursor: pointer;
}
.result {
  margin-top: 15px;
}