body {
  font-family: Arial, sans-serif;
  text-align: center;
  padding: 20px;
}
.fib-container {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 20px;
}
.fib-box {
  width: 50px;
  height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 5px;
  background-color: #f0f0f0;
  border: 1px solid #ddd;
  font-weight: bold;
}
.buttons {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}
.buttons button {
  margin: 0 10px;
  padding: 10px 20px;
  font-size: 16px;
  width: fit-content;
}

let gen;
let result;

function* fibonacci(n) {
  let a = 0, b = 1;
  for (let i = 0; i < n; ++i) {
    let temp = a;
    a = b;
    b = temp + b;
    yield a;
  }
}

function startVisualization() {
  const fibContainer = document.getElementById('fibContainer');
  fibContainer.innerHTML = '';
  gen = fibonacci(20);
  result = gen.next();

  document.getElementById('stepBtn').disabled = false;
  document.getElementById('resetBtn').disabled = false;
}

function stepVisualization() {
  if (result && !result.done) {
    const fibContainer = document.getElementById('fibContainer');
    const box = document.createElement('div');
    box.className = 'fib-box';
    box.textContent = result.value;
    fibContainer.appendChild(box);

    result = gen.next();
    if (result.done) {
      document.getElementById('stepBtn').disabled = true;
    }
  }
}


function resetVisualization() {
  const fibContainer = document.getElementById('fibContainer');
  fibContainer.innerHTML = '';
  document.getElementById('stepBtn').disabled = true;
  document.getElementById('resetBtn').disabled = true;
}

document.getElementById('startBtn').addEventListener('click', startVisualization);
document.getElementById('stepBtn').addEventListener('click', stepVisualization);
document.getElementById('resetBtn').addEventListener('click', resetVisualization);