/* Áudio – centralização e escala */
.audio-container{
  width:100%;
  text-align:center;
  margin:.75rem 0;
  padding:.5rem 0;
}
.audio-container audio{
  display:inline-block; /* respeita text-align */
  width:210px;
  height:32px;
  transform:scale(.7);
  transform-origin:center center;
}

/* Responsivo */
@media (max-width:768px){
  .audio-container audio{
    width:180px;height:28px;transform:scale(.6);
  }
}
@media (max-width:480px){
  .audio-container audio{
    width:140px;height:24px;transform:scale(.55);
  }
}
@media (max-width:320px){
  .audio-container audio{
    width:120px;height:20px;transform:scale(.5);
  }
}