/* ボタンの基本見た目（SVGアイコンを中央に表示） */
[data-mh-speaker] {
  width: 42px;
  height: 42px;
  padding: 0;
  border: none;
  background: transparent;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: opacity .18s ease;
}

/* 状態に応じたスタイル */
[data-mh-speaker].is-muted { opacity: 0.55; }
[data-mh-speaker].is-on    { opacity: 1;    }

[data-mh-speaker] img[data-mh-speaker-icon] {
  width: 26px;
  height: 26px;
  display: block;
  pointer-events: none;
}