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

html, body {
  height: 100%;
  background: #080d15;
}

body {
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: "PingFang SC", "Microsoft YaHei", "Segoe UI", system-ui, sans-serif;
  overflow: hidden;
}

canvas#game {
  display: block;
  /* 等比缩放：宽度受视口宽高共同约束，保持 5:3 */
  width: min(960px, 100vw, calc(100vh * 5 / 3));
  aspect-ratio: 5 / 3;
  background: #0e1a2f;
  border-radius: 14px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  box-shadow: 0 30px 60px -30px rgba(0, 0, 0, 0.9);
}