body {
  font-family: Arial, sans-serif;
  background: #111;
  color: #eee;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
}

.calculator-container {
  background: #1c1c1c;
  padding: 25px;
  border-radius: 12px;
  max-width: 500px;
  width: 100%;
  box-shadow: 0 4px 12px rgba(0,0,0,0.6);
}

h1 {
  text-align: center;
  color: #ffcc00;
  margin-bottom: 20px;
}

label {
  display: block;
  margin: 10px 0 5px;
}

input {
  width: 100%;
  padding: 10px;
  border: none;
  border-radius: 8px;
  margin-bottom: 15px;
}

button {
  width: 100%;
  padding: 12px;
  background: #ffcc00;
  border: none;
  border-radius: 8px;
  font-weight: bold;
  cursor: pointer;
}

button:hover {
  background: #ffdb4d;
}

#result {
  margin-top: 20px;
  padding: 15px;
  background: #222;
  border-radius: 8px;
  text-align: center;
}

canvas {
  margin-top: 20px;
  width: 100%;
  height: 300px;
  background: #fff;
  border-radius: 8px;
}