.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 20px;
}

h1 {
  text-align: center;
  margin-top: 0;
}

h2 {
  text-align: center;
  margin-top: 0;
}

h3 {
  text-align: center;
  margin-top: 0;
}

p {
  text-align: center;
  margin-top: 0;
}

.form-group {
  display: flex;
  flex-direction: column;
  margin-bottom: 10px;
}

.form-group label {
  font-size: 16px;
  margin-bottom: 5px;
}

.form-group select, 
.form-group input {
  font-size: 16px;
  padding: 10px;
  border-radius: 5px;
  margin-bottom: 5px;
  border: 1px solid #ccc;
}

.form-group input {
  margin-top: 5px;
}

.btn {
  background-color: #4CAF50;
  color: white;
  padding: 12px 20px;
  border: none;
  border-radius: 5px;
  font-size: 16px;
  cursor: pointer;
}

.btn:hover {
  background-color: #3e8e41;
}

.result {
  font-size: 20px;
  font-weight: bold;
  margin-top: 20px;
}