body {
  margin: 0;
  background: black;
  color: white;
  font-family: monospace;
  overflow: hidden;
}

canvas#matrix {
  position: fixed;
  top: 0;
  left: 0;
  z-index: -1;
}

.center {
  text-align: center;
  margin-top: 30px;
}

button {
  padding: 10px 20px;
  background: deeppink;
  color: white;
  border: none;
  border-radius: 6px;
  font-size: 18px;
  cursor: pointer;
  margin-bottom: 20px;
}

canvas#gameCanvas {
  background: #111;
  border: 2px solid #f0f;
  box-shadow: 0 0 20px #f0f;
  display: block;
  margin: 0 auto;
}