* { margin: 0; padding: 0; box-sizing: border-box; }
body { overflow: hidden; background: #000; }
canvas { display: block; }

/* ── VR 按钮 ── */
#vr-btn-wrap {
  position: fixed;
  bottom: 28px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 9999;
}

#vrBtn {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 28px;
  background: rgba(10, 10, 10, 0.82);
  color: #ffffff;
  border: 2px solid rgba(255,255,255,0.35);
  border-radius: 50px;
  font-size: 15px;
  font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
  cursor: pointer;
  backdrop-filter: blur(8px);
  letter-spacing: 0.05em;
  transition: background 0.2s, border-color 0.2s;
}

#vrBtn:hover {
  background: rgba(30,30,30,0.95);
  border-color: rgba(255,255,255,0.65);
}

#vrIcon { font-size: 20px; line-height: 1; }

#vrBtn.active {
  background: rgba(20,80,200,0.82);
  border-color: rgba(100,160,255,0.7);
}

/* VR全屏后隐藏按钮 */
.vr-mode #vr-btn-wrap { display: none; }