body {
  margin: 0;
  padding: 0;
  font-family: Arial, sans-serif;
  background: #f2f2f2;
  color: #333;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}

.container {
  background: #fff;
  padding: 2rem;
  border-radius: 16px;
  box-shadow: 0 0 20px rgba(0,0,0,0.1);
  max-width: 500px;
  width: 90%;
  text-align: center;
}

h1 {
  margin-bottom: 0.5rem;
}

p {
  font-size: 1rem;
  margin-bottom: 1rem;
}

button {
  padding: 0.7rem 1.5rem;
  margin: 0.5rem;
  font-size: 1rem;
  border: none;
  border-radius: 8px;
  background-color: #4CAF50;
  color: white;
  cursor: pointer;
  transition: background 0.3s;
}

button:hover {
  background-color: #45a049;
}

canvas {
  margin-top: 1rem;
  max-width: 100%;
  border-radius: 12px;
  border: 1px solid #ccc;
  display: none;
}

input {
  margin-top: 1rem;
  width: 100%;
  padding: 0.6rem;
  font-size: 1rem;
  border-radius: 8px;
  border: 1px solid #ccc;
  box-sizing: border-box;
}

.hidden {
  display: none;
}