* {
  margin: 0;
  padding: 0;
  box-sizing: inherit;
}

body {
  background-color: black;
  color: white;
  text-align: center;
  font-family: Arial, sans-serif;
}

canvas {
  background: green;
  border: 4px solid white;
  display: block;
  margin: 20px auto;
}

button {
  padding: 10px 20px;
  font-size: 18px;
  cursor: pointer;
  background-color: yellow;
  border: none;
  font-weight: bold;
}