/* ================================================
   音频引导播放器 — 共享样式
   所有颜色通过 CSS 变量适配各课程主题
   依赖: --color-primary, --color-primary-light,
         --color-primary-rgb, --color-surface,
         --color-border, --color-bg-alt,
         --color-text, --color-text-secondary,
         --color-text-muted, --radius-lg, --radius-sm,
         --shadow-sm, --shadow-md, --shadow-lg,
         --space-*, --touch-target-sm, --transition
   ================================================ */

/* === Audio Guide — In-page Card === */
.audio-guide-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5) var(--space-6);
  box-shadow: var(--shadow-sm);
  margin-bottom: var(--space-6);
  transition: var(--transition);
}

@media (hover: hover) {
  .audio-guide-card:hover {
    box-shadow: var(--shadow-md);
  }
}

.audio-guide-header {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  margin-bottom: var(--space-4);
}

.audio-header-play-btn {
  min-height: var(--touch-target-sm);
  border: none;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
  color: #fff;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  padding: var(--space-1) var(--space-4);
  transition: var(--transition);
  white-space: nowrap;
  flex-shrink: 0;
  margin-left: auto;
}

/* Group: ambient btn + play btn */
.audio-header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  margin-left: auto;
  flex-shrink: 0;
}
.audio-header-actions .audio-header-play-btn {
  margin-left: 0;
}

.audio-guide-settings-btn {
  min-height: var(--touch-target-sm);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg-alt);
  color: var(--color-text-muted);
  padding: var(--space-1) var(--space-2);
  cursor: pointer;
  transition: var(--transition);
  flex-shrink: 0;
  line-height: 1;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Language toggle button (EN / 中) */
.audio-lang-toggle {
  min-height: var(--touch-target-sm);
  min-width: var(--touch-target-sm);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg-alt);
  color: var(--color-text-secondary);
  font-size: 0.78rem;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-1) var(--space-2);
  line-height: 1;
}

.audio-lang-toggle.zh {
  background: rgba(var(--color-primary-rgb), 0.12);
  color: var(--color-primary);
  border-color: rgba(var(--color-primary-rgb), 0.3);
}

@media (hover: hover) {
  .audio-lang-toggle:hover {
    border-color: var(--color-primary);
    color: var(--color-primary);
  }
}

@media (hover: hover) {
  .audio-header-play-btn:hover {
    filter: brightness(1.08);
    transform: translateY(-1px);
  }
}

.audio-guide-icon {
  font-size: 2rem;
  line-height: 1;
  flex-shrink: 0;
}

.audio-guide-title {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
  margin: 0 0 var(--space-1) 0;
}

.audio-guide-desc {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  margin: 0;
  line-height: 1.5;
}

.audio-guide-play-all {
  min-height: var(--touch-target-sm);
  border: none;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
  color: #fff;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  padding: var(--space-1) var(--space-4);
  transition: var(--transition);
  white-space: nowrap;
  flex-shrink: 0;
}

/* Play/pause icon button in control bar */
.audio-guide-play-pause {
  width: var(--touch-target-sm);
  height: var(--touch-target-sm);
  border: none;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
  color: #fff;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  flex-shrink: 0;
  padding: 0;
}

.audio-guide-play-pause svg {
  width: 16px;
  height: 16px;
}

@media (hover: hover) {
  .audio-guide-play-pause:hover {
    filter: brightness(1.08);
    transform: translateY(-1px);
  }
}

/* Prev / Next / Skip icon buttons */
.audio-ctrl-icon {
  width: var(--touch-target-sm);
  height: var(--touch-target-sm);
  border: none;
  border-radius: var(--radius-sm);
  background: transparent;
  color: var(--color-text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  flex-shrink: 0;
  padding: 0;
}

.audio-ctrl-icon svg {
  width: 18px;
  height: 18px;
}

@media (hover: hover) {
  .audio-ctrl-icon:hover {
    color: var(--color-primary);
    background: rgba(var(--color-primary-rgb), 0.08);
  }
}

/* Loop / repeat mode toggle */
.audio-guide-loop-btn {
  width: var(--touch-target-sm);
  height: var(--touch-target-sm);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg-alt);
  color: var(--color-text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
  flex-shrink: 0;
  padding: 0;
}

.audio-guide-loop-btn svg {
  width: 18px;
  height: 18px;
}

.audio-guide-loop-btn.active {
  color: var(--color-primary);
  border-color: var(--color-primary);
  background: rgba(var(--color-primary-rgb), 0.08);
}

@media (hover: hover) {
  .audio-guide-loop-btn:hover {
    color: var(--color-primary);
    border-color: var(--color-primary);
  }
}

@media (hover: hover) {
  .audio-guide-play-all:hover {
    filter: brightness(1.08);
    transform: translateY(-1px);
  }
}

/* Now playing area */
.audio-now-playing {
  padding: var(--space-3) var(--space-4);
  background: var(--color-bg-alt);
  border-radius: var(--radius-sm);
  margin-bottom: var(--space-4);
}

.audio-now-info {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  margin-bottom: var(--space-3);
}

.audio-now-label {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-primary);
  flex-shrink: 0;
}

.audio-now-title {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--color-text);
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.audio-guide-progress-wrap {
  position: relative;
  height: 26px;
  display: flex;
  align-items: center;
  margin-bottom: var(--space-2);
  cursor: pointer;
}

.audio-seek-track {
  position: absolute;
  left: 0; right: 0;
  height: 6px;
  border-radius: 3px;
  background: var(--color-border);
  overflow: hidden;
  pointer-events: none;
}

.audio-seek-fill {
  height: 100%;
  width: 0;
  background: var(--color-primary);
  border-radius: 3px;
  transition: width 0.15s linear;
}

.audio-guide-seek {
  -webkit-appearance: none;
  appearance: none;
  position: relative;
  width: 100%;
  height: 26px;
  background: transparent;
  outline: none;
  cursor: pointer;
  margin: 0;
  padding: 0;
  touch-action: none;
  z-index: 1;
}

.audio-guide-seek::-webkit-slider-runnable-track {
  height: 6px;
  border-radius: 3px;
  background: transparent;
}

.audio-guide-seek::-moz-range-track {
  height: 6px;
  border-radius: 3px;
  background: transparent;
}

.audio-guide-seek::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--color-primary);
  cursor: pointer;
  border: 2px solid #fff;
  box-shadow: 0 1px 4px rgba(0,0,0,.18);
  margin-top: -5px;
}

.audio-guide-time {
  font-size: 0.78rem;
  color: var(--color-text-muted);
  font-variant-numeric: tabular-nums;
}

.audio-guide-ctrl-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.audio-guide-ctrl-row.standalone {
  display: none;
}

.audio-guide-ctrl-btns {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.audio-guide-speed-btn {
  min-height: var(--touch-target-sm);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg-alt);
  color: var(--color-text-secondary);
  font-size: 0.82rem;
  font-weight: 600;
  padding: var(--space-1) var(--space-3);
  cursor: pointer;
  transition: var(--transition);
  flex-shrink: 0;
}

/* === Segment List === */
.audio-seg-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.audio-seg-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-3);
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.audio-seg-item.active {
  background: rgba(var(--color-primary-rgb), 0.08);
}

.audio-seg-item.excluded {
  opacity: 0.45;
}

.audio-seg-item.unavailable {
  opacity: 0.38;
  pointer-events: none;
}

.audio-seg-play {
  width: var(--touch-target-sm);
  height: var(--touch-target-sm);
  border: 1px solid var(--color-border);
  border-radius: 50%;
  background: var(--color-bg-alt);
  color: var(--color-text-secondary);
  font-size: 0.82rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: var(--transition);
}

.audio-seg-item.active .audio-seg-play {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}

.audio-seg-play:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.audio-seg-title {
  flex: 1;
  font-size: 0.9rem;
  color: var(--color-text);
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.audio-seg-duration {
  flex-shrink: 0;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

/* Toggle switch */
.audio-seg-toggle {
  position: relative;
  width: 38px;
  height: 22px;
  flex-shrink: 0;
}

.audio-seg-toggle input {
  opacity: 0;
  width: 0;
  height: 0;
  position: absolute;
}

.audio-seg-toggle-slider {
  position: absolute;
  inset: 0;
  background: var(--color-border);
  border-radius: 11px;
  cursor: pointer;
  transition: var(--transition);
}

.audio-seg-toggle-slider::before {
  content: '';
  position: absolute;
  width: 16px;
  height: 16px;
  left: 3px;
  top: 3px;
  background: #fff;
  border-radius: 50%;
  transition: var(--transition);
}

.audio-seg-toggle input:checked + .audio-seg-toggle-slider {
  background: var(--color-primary);
}

.audio-seg-toggle input:checked + .audio-seg-toggle-slider::before {
  transform: translateX(16px);
}

/* === Audio Mini Player (floating) === */
.audio-mini-player {
  position: fixed;
  bottom: max(96px, calc(env(safe-area-inset-bottom, 0px) + 80px));
  right: var(--space-4);
  z-index: 9997;
  display: flex;
  align-items: center;
  gap: var(--space-3);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-3) var(--space-4);
  box-shadow: var(--shadow-lg);
  max-width: 320px;
  opacity: 0;
  transform: translateY(16px) scale(0.95);
  pointer-events: none;
  transition: opacity 0.25s ease, transform 0.25s ease;
}

.audio-mini-player.visible {
  opacity: 1;
  transform: translateY(0) scale(1);
  pointer-events: auto;
}

.audio-mini-play,
.audio-mini-close,
.audio-mini-prev,
.audio-mini-next {
  width: var(--touch-target-sm);
  height: var(--touch-target-sm);
  border: none;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  flex-shrink: 0;
  transition: var(--transition);
}

.audio-mini-play {
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-primary));
  color: #fff;
}

.audio-mini-prev,
.audio-mini-next {
  background: var(--color-bg-alt);
  color: var(--color-text-secondary);
  font-size: 0.85rem;
}

.audio-mini-close {
  background: var(--color-bg-alt);
  color: var(--color-text-muted);
  font-size: 0.85rem;
}

.audio-mini-info {
  flex: 1;
  min-width: 0;
}

.audio-mini-title {
  display: block;
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--color-text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  margin-bottom: 4px;
}

.audio-mini-bar-wrap {
  width: 100%;
  height: 4px;
  background: var(--color-border);
  border-radius: 2px;
  overflow: hidden;
  cursor: pointer;
  padding: 8px 0;
  margin: -8px 0;
  background-clip: content-box;
}

.audio-mini-bar {
  height: 100%;
  width: 0;
  background: var(--color-primary);
  border-radius: 2px;
  transition: width 0.3s linear;
}

/* Mobile adjustments */
@media (max-width: 480px) {
  .audio-guide-card {
    padding: var(--space-4) var(--space-4);
  }
  .audio-guide-desc {
    font-size: 0.85rem;
  }
  .audio-guide-header {
    flex-wrap: wrap;
  }
  .audio-guide-ctrl-btns {
    gap: var(--space-1);
  }
  .audio-ctrl-icon {
    width: 30px;
    height: 30px;
  }
  .audio-ctrl-icon svg {
    width: 16px;
    height: 16px;
  }
  .audio-guide-loop-btn {
    width: 30px;
    height: 30px;
  }
  .audio-guide-loop-btn svg {
    width: 16px;
    height: 16px;
  }
  .audio-guide-speed-btn {
    min-height: 30px;
    padding: var(--space-1) var(--space-2);
    font-size: 0.78rem;
  }
  .audio-seg-item {
    gap: var(--space-2);
    padding: var(--space-2) var(--space-2);
  }
  .audio-seg-play {
    width: 30px;
    height: 30px;
    font-size: 0.72rem;
  }
  .audio-seg-title {
    font-size: 0.85rem;
  }
  .audio-seg-duration {
    display: none;
  }
  .audio-seg-toggle {
    width: 32px;
    height: 18px;
  }
  .audio-seg-toggle-slider {
    border-radius: 9px;
  }
  .audio-seg-toggle-slider::before {
    width: 13px;
    height: 13px;
    left: 2.5px;
    top: 2.5px;
  }
  .audio-seg-toggle input:checked + .audio-seg-toggle-slider::before {
    transform: translateX(14px);
  }
  .audio-mini-player {
    left: var(--space-3);
    right: var(--space-3);
    max-width: none;
    bottom: max(86px, calc(env(safe-area-inset-bottom, 0px) + 72px));
  }
}

@media (hover: hover) {
  .audio-guide-settings-btn:hover {
    color: var(--color-text);
    background: rgba(128, 128, 128, 0.08);
  }
}

/* ===== Audio Settings Dialog ===== */
.audio-settings-backdrop {
  position: fixed;
  inset: 0;
  z-index: 10000;
  background: rgba(0, 0, 0, 0.45);
  backdrop-filter: blur(3px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  animation: ambBackdropIn 0.2s ease;
}
@keyframes ambBackdropIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}
.audio-settings-dialog {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  max-width: 420px;
  width: 100%;
  max-height: 80vh;
  display: flex;
  flex-direction: column;
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.18);
  animation: ambDialogIn 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}
@keyframes ambDialogIn {
  from { opacity: 0; transform: translateY(16px) scale(0.97); }
  to   { opacity: 1; transform: translateY(0) scale(1); }
}
.audio-settings-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-4) var(--space-5);
  border-bottom: 1px solid var(--color-border);
  flex-shrink: 0;
}
.audio-settings-title {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-text);
}
.audio-settings-close {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: none;
  background: transparent;
  color: var(--color-text-muted);
  font-size: 1rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}
@media (hover: hover) {
  .audio-settings-close:hover {
    background: var(--color-bg-alt);
    color: var(--color-text);
  }
}
.audio-settings-body {
  padding: 0;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior: contain;
  border-radius: 0 0 var(--radius-lg) var(--radius-lg);
}
.audio-settings-section {
  padding: var(--space-4) var(--space-5);
  margin-bottom: 0;
}
.audio-settings-section + .audio-settings-section {
  border-top: 1px solid var(--color-border);
}
.audio-settings-section:last-child {
  padding-bottom: var(--space-5);
}
.audio-settings-heading {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin: 0 0 var(--space-3);
}
.amb-slow-hint {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  white-space: nowrap;
}