* { box-sizing: border-box; margin: 0; padding: 0; }
html, body {
  height: 100%;
  background: #0b0c10;
  color: #fff;
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}
#game {
  position: relative;
  width: 960px;
  max-width: 100vw;
  aspect-ratio: 16 / 9;
  box-shadow: 0 0 40px rgba(0,0,0,0.7);
}
canvas {
  width: 100%;
  height: 100%;
  display: block;
  background: linear-gradient(#1a1c29, #0b0c10);
  border-radius: 8px;
}
#ui {
  position: absolute;
  top: 12px;
  left: 18px;
  right: 18px;
  display: flex;
  justify-content: space-between;
  font-size: 18px;
  font-weight: 700;
  text-shadow: 0 2px 4px rgba(0,0,0,0.8);
  pointer-events: none;
}
#overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(0,0,0,0.72);
  border-radius: 8px;
  text-align: center;
  gap: 14px;
}
#overlay h1 {
  font-size: 64px;
  letter-spacing: 4px;
  color: #66fcf1;
  text-shadow: 0 0 20px rgba(102,252,241,0.4);
}
#overlay p { max-width: 480px; color: #c5c6c7; font-size: 16px; }
#startBtn {
  padding: 12px 36px;
  font-size: 20px;
  font-weight: 700;
  color: #0b0c10;
  background: #66fcf1;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: transform .1s, background .2s;
}
#startBtn:hover { background: #45a29e; transform: scale(1.05); }
.hidden { display: none !important; }