<div class="calculator-container">
  <h1>Find Your Birth Year </h1>

  <div class="input-group">
    <label for="ageInput">Enter Your Age:</label>
    <input type="number" id="ageInput" placeholder="e.g., 30">
  </div>

  <button id="calculateButton">Calculate!</button>

  <div id="results-container" class="results hidden">
    <p>Your Birth Year: <span id="birthYearOutput"></span></p>
  </div>
</div>

body {
  font-family: sans-serif;
  background-color: #f4f4f4;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
}

.calculator-container {
  background-color: #fff;
  padding: 30px;
  border-radius: 10px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  text-align: center;
  width: 400px;
}

h1 {
  color: #333;
  margin-bottom: 25px;
}

.input-group {
  margin-bottom: 20px;
}

label {
  display: block;
  margin-bottom: 8px;
  color: #555;
  font-weight: bold;
}

input[type="number"] {
  width: 100%;
  padding: 12px;
  border: 1px solid #ccc;
  border-radius: 5px;
  font-size: 16px;
  box-sizing: border-box; /* Important to include padding in width */
}

button {
  background-color: #5cb85c; /* Green button */
  color: white;
  padding: 12px 25px;
  border: none;
  border-radius: 5px;
  font-size: 18px;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

button:hover {
  background-color: #4cae4c; /* Darker green on hover */
}

.results,
.error {
  margin-top: 25px;
  padding: 15px;
  border-radius: 5px;
  background-color: #e9ecef;
  border: 1px solid #ced4da;
}

.results p,
.error p {
  margin: 0;
  color: #495057;
  font-size: 16px;
}

.results.hidden,
.error.hidden {
  display: none; /* Initially hide results and error */
}

.completed {
  /* Example of reusing .completed class if you want to add it later */
  text-decoration: line-through;
  color: gray;
}

function getBirthYear(age) {
  const currentYear = new Date().getFullYear(); // Use current year dynamically
  const birthYear = currentYear - age;
  return birthYear;
}

document.addEventListener("DOMContentLoaded", () => {
  const calculateButton = document.getElementById("calculateButton");
  const ageInput = document.getElementById("ageInput");
  const birthYearOutput = document.getElementById("birthYearOutput");

  const resultsContainer = document.getElementById("results-container");

  calculateButton.addEventListener("click", () => {
    const ageInputValue = parseInt(ageInput.value); // Get input value as number

    const birthYear = getBirthYear(ageInputValue); // Calculate birth year using function

    birthYearOutput.textContent = birthYear;
    resultsContainer.classList.remove("hidden"); // Show results
  });
});