:root {
  /* カラーパレット */
  --color-primary: #ebf2f1;
  --color-secondary: #ffffff;
  --color-tertiary: #009e96;
  --color-audio-control:#434648;

  /* タッチターゲットの最小サイズ */
  --touch-target-size: 44px;

  /* インタラクションの設定 */
  --scale-active: 0.95;
  --transition-duration: 0.1s;
}

/* ルート要素のスタイル */
audio-player {
  display: block;
  width: 100%;
  margin: 5px 0;
  border: none;
  box-sizing: border-box;
  padding: 10px;
}


.audio-player body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
    Ubuntu, Cantarell, sans-serif;
  background-color: #f5f5f7;
  color: #333;
  line-height: 1.6;
  padding: 20px;
}

.audio-player .container {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 15px;
}

.audio-player header {
  text-align: center;
  margin-bottom: 40px;
}

.audio-player h1 {
  font-size: 1.5rem;
  margin-bottom: 10px;
  color: #333;
}

.audio-player .description {
  font-size: 1.1rem;
  color: #666;
  max-width: 600px;
  margin: 0 auto;
}

.audio-player .player-section {
  margin-bottom: 60px;
  padding: 30px;
  border-radius: 16px;
  background-color: #fff;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

.audio-player .section-title {
  font-size: 1.8rem;
  margin-bottom: 20px;
  text-align: center;
}

/* プログレスバー */
.progress-wrapper {
  display: flex;
  flex-direction: row;
  gap: 5px;
}

.audio-player .progress-container {
  width: 100%;
  height: 6px;
  background-color: white;
  border-radius: 3px;
  cursor: pointer;
  margin-top: 9px;
  position: relative;
}

.audio-player .progress-bar {
  height: 6px;
  border-radius: 3px;
  width: 0;
  background-color: #9aa6b2;
  position: relative;
}

/* 時間表示 */
.audio-player .time-display {
  display: flex;
  justify-content: space-between;
  margin-bottom: 20px;
  font-size: 14px;
  color: #666;
}

/* コントロールエリア */
.player-controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: relative;
  width: 100%;
  margin-bottom: 5px;
}

/* 速度設定ボタン */
.control-btn {
  background: none;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
  color: var(--color-audio-control);
}

.control-btn:hover {
  opacity: 0.8;
}

/* 速度コントロール */
.speed-control {
  position: relative;
  min-width: var(--touch-target-size);
}

.speed-btn {
  cursor: pointer;
  pointer-events: auto;
  position: relative;
  z-index: 1;
  font-weight: bold;
}

.speed-options {
  display: flex;
  flex-direction: column;
  gap: 5px;
  padding: 8px;
}

.speed-option {
  background: none;
  border: none;
  padding: 5px 10px;
  cursor: pointer;
  border-radius: 4px;
  font-size: 15px;
}

.speed-option:hover {
  background-color: #f0f0f0;
}

/* ツールチップ */
.tooltip.speed-tooltip {
  position: absolute;
  background: rgba(142, 141, 141, 0.9);
  border-radius: 4px;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
  display: none;
  z-index: 1000;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%);
  margin-bottom: 5px;
  margin-left: 35px;
  padding: 10px;
}

.tooltip.speed-tooltip.active {
  display: block;
}

/* 再生コントロール */
.playback-controls {
  display: flex;
  align-items: center;
  justify-content: center;
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
}

/* スキップボタン */
.skip-btn {
  color: var(--color-audio-control);
  font-size: 20px;
  background: none;
  border: none;
  cursor: pointer;
  min-width: var(--touch-target-size);
  min-height: var(--touch-target-size);
}

.skip-btn:hover {
  transform: scale(1.1);
}

/* 再生ボタン */
.play-pause-btn {
  color: var(--color-audio-control);
  font-size: 45px;
  border: none;
  background: none;
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: var(--touch-target-size);
  min-height: var(--touch-target-size);
  padding: 13px;
}

.play-pause-btn:active,
.skip-btn:active,
.speed-btn:active {
  transform: scale(var(--scale-active));
  transition: transform var(--transition-duration) ease;
  outline: none; /* フォーカス時のアウトラインを削除 */
  -webkit-tap-highlight-color: transparent; /* モバイル端末でのタップ時のハイライトを削除 */
}