:root {
  --bg-primary: #000000; /* 純黒 = 加算式ディスプレイでは透明 */
}

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

html, body {
  width: 600px;
  height: 600px;
  overflow: hidden;
  background: var(--bg-primary);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Hiragino Sans', 'Yu Gothic', sans-serif;
  -webkit-user-select: none;
  user-select: none;
}

#app {
  width: 600px;
  height: 600px;
  position: relative;
}

#table {
  display: block;
  width: 600px;
  height: 600px;
  background: var(--bg-primary);
}