#bgSoundBtn{position:fixed;left:16px;bottom:24px;z-index:8000;width:46px;height:46px;border-radius:50%;border:1px solid rgba(218,172,82,0.8);
  background:rgba(70,18,34,.92);color:#F6D98A;display:flex;align-items:center;justify-content:center;cursor:pointer;
  box-shadow:0 6px 20px rgba(0,0,0,.5),0 0 18px rgba(201,147,46,.18);-webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px);transition:transform .2s;}
#bgSoundBtn:hover{transform:scale(1.06);}
#bgSoundBtn svg{width:22px;height:22px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round;}
#bgSoundBtn.on{background:linear-gradient(120deg,#F6D98A 0%,#D4A445 45%,#C9932E 100%);color:#1B0708;}
#bgSoundBtn .ring{position:absolute;inset:-4px;border-radius:50%;border:2px solid rgba(246,217,138,.6);opacity:0;}
#bgSoundBtn.on .ring{animation:bgPulse 1.8s ease-out infinite;}
@keyframes bgPulse{0%{opacity:.6;transform:scale(1)}100%{opacity:0;transform:scale(1.4)}}
#bgAudioBox{position:fixed;width:1px;height:1px;left:-9999px;top:-9999px;overflow:hidden;pointer-events:none;}
@media(max-width:768px){ #bgSoundBtn{bottom:84px;} }   /* clear the bottom tab bar */