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

:root {
  --bg-color: #1a1a2e;
  --panel-bg: #16213e;
  --panel-border: #0f3460;
  --text-color: #e0e0e0;
  --text-muted: #888;
  --accent: #e94560;
  --grid-line: rgba(255, 255, 255, 0.05);
  --font-main: 'Courier New', Courier, monospace;
  --cell-size: 30px;
}

html, body {
  height: 100%;
  background: var(--bg-color);
  color: var(--text-color);
  font-family: var(--font-main);
  overflow: hidden;
}

#game-container {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 20px;
  height: 100vh;
  padding: 20px;
}

#board-wrapper {
  position: relative;
  flex-shrink: 0;
}

#side-panel {
  display: flex;
  flex-direction: column;
  gap: 16px;
  width: 160px;
}

#overlay {
  position: fixed;
  inset: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 100;
}

#overlay .screen {
  text-align: center;
}

@media (max-width: 600px) {
  #game-container {
    flex-direction: column;
    gap: 10px;
    padding: 10px;
  }
  #side-panel {
    flex-direction: row;
    flex-wrap: wrap;
    width: 100%;
    justify-content: center;
  }
}