/* ============================================
   MFF Editor — Premium Dark Theme Design System
   ============================================ */

:root {
  /* Color Palette */
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-tertiary: #1c2128;
  --bg-elevated: #21262d;
  --bg-glass: rgba(22, 27, 34, 0.85);

  --surface-1: #272d36;
  --surface-2: #2d333b;
  --surface-3: #373e47;

  --accent-primary: #58a6ff;
  --accent-primary-hover: #79bbff;
  --accent-primary-dim: rgba(88, 166, 255, 0.15);
  --accent-success: #3fb950;
  --accent-success-hover: #56d364;
  --accent-success-dim: rgba(63, 185, 80, 0.15);
  --accent-danger: #f85149;
  --accent-danger-hover: #ff6b61;
  --accent-danger-dim: rgba(248, 81, 73, 0.15);
  --accent-warning: #d29922;
  --accent-purple: #bc8cff;

  --text-primary: #e6edf3;
  --text-secondary: #8b949e;
  --text-tertiary: #6e7681;
  --text-on-accent: #ffffff;

  --border-default: #30363d;
  --border-muted: #21262d;
  --border-accent: rgba(88, 166, 255, 0.4);

  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 12px;
  --space-lg: 16px;
  --space-xl: 24px;
  --space-2xl: 32px;
  --space-3xl: 48px;

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 20px rgba(88, 166, 255, 0.15);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Layout */
  --sidebar-width: 300px;
  --toolbar-height: 56px;
  --audio-bar-height: 54px;
}

/* ====== Reset & Base ====== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html, body {
  height: 100%;
  overflow: hidden;
}

body {
  font-family: var(--font-family);
  font-size: 14px;
  color: var(--text-primary);
  background: var(--bg-primary);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

code {
  font-family: var(--font-mono);
  background: var(--surface-1);
  padding: 2px 6px;
  border-radius: var(--radius-sm);
  font-size: 0.9em;
  color: var(--accent-purple);
}

.hidden {
  display: none !important;
}

/* ====== Buttons ====== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  font-family: var(--font-family);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all var(--transition-fast);
  white-space: nowrap;
}
.btn svg {
  pointer-events: none;
}

.btn--primary {
  background: var(--accent-primary);
  color: var(--text-on-accent);
}
.btn--primary:hover {
  background: var(--accent-primary-hover);
  box-shadow: var(--shadow-glow);
  transform: translateY(-1px);
}

.btn--success {
  background: var(--accent-success);
  color: var(--text-on-accent);
}
.btn--success:hover {
  background: var(--accent-success-hover);
  transform: translateY(-1px);
}

.btn--danger {
  background: var(--accent-danger);
  color: var(--text-on-accent);
}
.btn--danger:hover {
  background: var(--accent-danger-hover);
}

.btn--ghost {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border-default);
}
.btn--ghost:hover {
  background: var(--surface-1);
  color: var(--text-primary);
  border-color: var(--border-accent);
}

.btn--sm {
  padding: var(--space-xs) var(--space-sm);
  font-size: 12px;
}

.btn--icon {
  padding: var(--space-sm);
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  border-radius: var(--radius-sm);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}
.btn--icon svg {
  pointer-events: none;
}
.btn--icon:hover {
  background: var(--surface-1);
  color: var(--text-primary);
}
.btn--icon.danger:hover {
  background: var(--accent-danger-dim);
  color: var(--accent-danger);
}

/* ====== Drop Zone ====== */
.drop-zone {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-primary);
  z-index: 100;
}

.drop-zone__content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-lg);
  padding: var(--space-3xl);
  border: 2px dashed var(--border-default);
  border-radius: var(--radius-xl);
  text-align: center;
  transition: all var(--transition-normal);
  max-width: 500px;
  cursor: pointer;
}

.drop-zone.drag-over .drop-zone__content {
  border-color: var(--accent-primary);
  background: var(--accent-primary-dim);
  transform: scale(1.02);
}

.drop-zone__icon {
  color: var(--accent-primary);
  opacity: 0.7;
  animation: float 3s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-8px); }
}

.drop-zone__title {
  font-size: 32px;
  font-weight: 700;
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.drop-zone__subtitle {
  color: var(--text-secondary);
  font-size: 15px;
}

.drop-zone__loading {
  position: absolute;
  inset: 0;
  display: none;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: var(--space-lg);
  background: rgba(13, 17, 23, 0.95);
  backdrop-filter: blur(8px);
  color: var(--text-secondary);
}

.drop-zone__loading.active {
  display: flex;
}

.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border-default);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ====== Toolbar ====== */
.toolbar {
  height: var(--toolbar-height);
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-default);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--space-lg);
  gap: var(--space-md);
  backdrop-filter: blur(12px);
}

.toolbar__left,
.toolbar__right {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.toolbar__title {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
  margin-left: var(--space-sm);
}

.toolbar__btn {
  width: 36px;
  height: 36px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}
.toolbar__btn:hover {
  background: var(--surface-1);
  color: var(--text-primary);
}

/* ====== Editor Layout ====== */
.editor-app {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

.editor-layout {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* ====== Sidebar ====== */
.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-default);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.sidebar__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid var(--border-muted);
}

.sidebar__title {
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
}

.sidebar__btn {
  width: 28px;
  height: 28px;
  border: 1px solid var(--border-default);
  background: transparent;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all var(--transition-fast);
}
.sidebar__btn:hover {
  background: var(--accent-primary-dim);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

.sidebar__nav {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-sm);
}

.sidebar__nav::-webkit-scrollbar {
  width: 6px;
}
.sidebar__nav::-webkit-scrollbar-track {
  background: transparent;
}
.sidebar__nav::-webkit-scrollbar-thumb {
  background: var(--surface-3);
  border-radius: var(--radius-full);
}

/* Exercise list items */
.exercise-item {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  color: var(--text-secondary);
  font-size: 13px;
  margin-bottom: 2px;
  position: relative;
}

.exercise-item:hover {
  background: var(--surface-1);
  color: var(--text-primary);
}

.exercise-item.active {
  background: var(--accent-primary-dim);
  color: var(--accent-primary);
  font-weight: 500;
}

.exercise-item.active::before {
  content: '';
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 3px;
  background: var(--accent-primary);
  border-radius: var(--radius-full);
}

.exercise-item__num {
  width: 24px;
  height: 24px;
  border-radius: var(--radius-sm);
  background: var(--surface-2);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11px;
  font-weight: 600;
  flex-shrink: 0;
}

.exercise-item.active .exercise-item__num {
  background: var(--accent-primary);
  color: var(--text-on-accent);
}

.exercise-item__label {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.exercise-item__actions {
  display: none;
  gap: 2px;
}

.exercise-item:hover .exercise-item__actions {
  display: flex;
}

/* ====== Main Content ====== */
.main-content {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-xl);
  background: var(--bg-primary);
}

.main-content::-webkit-scrollbar {
  width: 8px;
}
.main-content::-webkit-scrollbar-track {
  background: transparent;
}
.main-content::-webkit-scrollbar-thumb {
  background: var(--surface-3);
  border-radius: var(--radius-full);
}

.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  gap: var(--space-lg);
  color: var(--text-tertiary);
}

/* ====== Settings Card (Audio & Player) ====== */
.settings-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-xl);
  overflow: hidden;
}

.settings-card__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
  background: var(--bg-tertiary);
  border-bottom: 1px solid var(--border-muted);
  cursor: pointer;
}

.settings-card__title {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--accent-primary);
}

.settings-card__toggle {
  transition: transform var(--transition-fast);
}

.settings-card__toggle.rotated {
  transform: rotate(-90deg);
}

.settings-card__body {
  padding: var(--space-lg);
  transition: max-height var(--transition-normal), padding var(--transition-normal);
  max-height: 600px;
  overflow: hidden;
}

.settings-card__body.collapsed {
  max-height: 0;
  padding-top: 0;
  padding-bottom: 0;
}

.settings-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-lg);
}

@media (max-width: 768px) {
  .settings-grid {
    grid-template-columns: 1fr;
  }
}

.settings-field {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.settings-field .form-label {
  display: flex;
  align-items: center;
  gap: 4px;
  margin-bottom: 0;
}

.settings-field .form-label svg {
  opacity: 0.6;
}

.settings-field .form-select,
.settings-field .form-input {
  font-size: 13px;
}

.settings-hint {
  font-size: 11px;
  color: var(--text-tertiary);
  line-height: 1.4;
}

/* ====== Exercise Editor ====== */
.exercise-editor {
  max-width: 900px;
  margin: 0 auto;
}

.exercise-header {
  margin-bottom: var(--space-xl);
}

.exercise-header__title-input {
  width: 100%;
  background: transparent;
  border: none;
  font-size: 24px;
  font-weight: 700;
  color: var(--text-primary);
  font-family: var(--font-family);
  padding: var(--space-sm) 0;
  border-bottom: 2px solid transparent;
  transition: border-color var(--transition-fast);
}

.exercise-header__title-input:focus {
  outline: none;
  border-bottom-color: var(--accent-primary);
}

.exercise-header__desc {
  margin-top: var(--space-md);
}

/* Tabs UI */
.tabs-nav {
  display: flex;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
  border-bottom: 1px solid var(--border-muted);
  padding-bottom: var(--space-xs);
}

.tab-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-family: var(--font-family);
  font-size: 13px;
  font-weight: 600;
  padding: var(--space-xs) var(--space-md);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.tab-btn:hover {
  background: var(--surface-1);
  color: var(--text-primary);
}

.tab-btn.active {
  background: var(--surface-2);
  color: var(--accent-primary);
  box-shadow: inset 0 -2px 0 var(--accent-primary);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
}

.html-preview-box {
  width: 100%;
  min-height: 100px;
  padding: var(--space-md);
  background: var(--surface-1);
  border: 1px solid var(--border-default);
  border-radius: 0 0 var(--radius-md) var(--radius-md);
  color: var(--text-primary);
  font-size: 14px;
  line-height: 1.6;
  overflow-wrap: break-word;
  outline: none;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.html-preview-box:focus {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-primary-dim);
}

.wysiwyg-toolbar {
  display: flex;
  gap: 2px;
  padding: var(--space-xs);
  background: var(--surface-2);
  border: 1px solid var(--border-default);
  border-bottom: none;
  border-radius: var(--radius-md) var(--radius-md) 0 0;
}

.wysiwyg-btn {
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.wysiwyg-btn:hover {
  background: var(--surface-3);
  color: var(--text-primary);
}

.wysiwyg-btn.active {
  background: var(--surface-3);
  color: var(--accent-primary);
}

/* Internal HTML Preview styles */
.html-preview-box b, .html-preview-box strong { font-weight: 700; color: #fff; }
.html-preview-box i, .html-preview-box em { font-style: italic; }
.html-preview-box u { text-decoration: underline; }
.html-preview-box gap { background: rgba(63, 185, 80, 0.2); border-bottom: 2px dashed var(--accent-success); color: var(--accent-success); padding: 0 4px; border-radius: 2px; font-weight: 600; font-family: var(--font-mono); }
.html-preview-box p { margin-bottom: 0.5em; }
.html-preview-box p:last-child { margin-bottom: 0; }

/* Form Fields */
.form-group {
  margin-bottom: var(--space-lg);
}

.form-label {
  display: block;
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-secondary);
  margin-bottom: var(--space-xs);
}

.form-input,
.form-textarea,
.form-select {
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  background: var(--surface-1);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-family);
  font-size: 14px;
  transition: all var(--transition-fast);
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-primary-dim);
}

.form-textarea {
  resize: vertical;
  min-height: 80px;
}

/* ====== Set/Question Cards ====== */
.set-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-lg);
  overflow: hidden;
  transition: all var(--transition-fast);
}

.set-card:hover {
  border-color: var(--border-accent);
  box-shadow: var(--shadow-sm);
}

.set-card__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
  background: var(--bg-tertiary);
  border-bottom: 1px solid var(--border-muted);
}

.set-card__type {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 12px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.set-card__type--description {
  color: var(--accent-purple);
}

.set-card__type--choices {
  color: var(--accent-primary);
}

.set-card__type--textarea {
  color: #e5a33d;
}

.set-card__type--gapfill {
  color: #3fb950;
}

.set-card__type--questions {
  color: #58a6ff;
}

.set-card__type--matches {
  color: #f778ba;
}

/* ====== Textarea Set ====== */
.textarea-set__info {
  margin-bottom: var(--space-md);
}

.textarea-set__limit {
  max-width: 140px;
}

.textarea-set__preview-box {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-lg);
  background: var(--surface-1);
  border: 1px dashed var(--border-default);
  border-radius: var(--radius-md);
  color: var(--text-tertiary);
  font-size: 13px;
  font-style: italic;
}

/* ====== Gap Fill Set ====== */
.gapfill-editor {
  font-family: var(--font-mono, 'Fira Code', monospace);
  font-size: 13px;
}

.gapfill-preview {
  margin-top: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  background: var(--surface-1);
  border-radius: var(--radius-sm);
  font-size: 12px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-xs);
}

.gapfill-preview__label {
  color: var(--text-tertiary);
  font-size: 11px;
  margin-right: var(--space-xs);
}

.gapfill-preview__gap {
  display: inline-block;
  padding: 2px 8px;
  background: rgba(63, 185, 80, 0.15);
  color: #3fb950;
  border-radius: var(--radius-full);
  font-size: 11px;
  font-weight: 600;
}

/* ====== Questions (Q&A) Set ====== */
.qa-row {
  display: flex;
  align-items: flex-start;
  gap: var(--space-sm);
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--border-muted);
}

.qa-row:last-child {
  border-bottom: none;
}

.qa-row__num {
  font-size: 12px;
  font-weight: 700;
  color: var(--text-tertiary);
  min-width: 20px;
  text-align: center;
  padding-top: 8px;
}

.qa-row__fields {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.qa-input {
  font-size: 13px;
}

.qa-input--answer {
  border-left: 3px solid #58a6ff;
  padding-left: var(--space-md);
}

/* ====== Matches Set ====== */
.match-header {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--border-muted);
  margin-bottom: var(--space-sm);
}

.match-header__col {
  flex: 1;
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-tertiary);
}

.match-header__spacer {
  width: 28px;
}

.match-row {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
}

.match-input {
  flex: 1;
  font-size: 13px;
}

.match-arrow {
  color: var(--text-tertiary);
  flex-shrink: 0;
  opacity: 0.5;
}

.set-card__actions {
  display: flex;
  gap: var(--space-xs);
}

.set-card__body {
  padding: var(--space-lg);
}

/* Description editor */
.desc-editor {
  width: 100%;
  min-height: 100px;
  padding: var(--space-md);
  background: var(--surface-1);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-family);
  font-size: 14px;
  resize: vertical;
  transition: border-color var(--transition-fast);
}

.desc-editor:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px var(--accent-primary-dim);
}

/* Choice items */
.choice-item {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-sm);
  background: var(--bg-primary);
  transition: all var(--transition-fast);
}

.choice-item:hover {
  border-color: var(--surface-3);
}

.choice-item.correct {
  border-color: var(--accent-success);
  background: var(--accent-success-dim);
}

.choice-radio {
  width: 20px;
  height: 20px;
  border: 2px solid var(--border-default);
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: all var(--transition-fast);
}

.choice-item.correct .choice-radio {
  border-color: var(--accent-success);
  background: var(--accent-success);
}

.choice-item.correct .choice-radio::after {
  content: '✓';
  color: white;
  font-size: 12px;
  font-weight: 700;
}

.choice-input {
  flex: 1;
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-family: var(--font-family);
  font-size: 14px;
  padding: var(--space-sm) 0;
}

.choice-input:focus {
  outline: none;
}

.choice-delete {
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.choice-item:hover .choice-delete {
  opacity: 1;
}

.add-choice-btn {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  width: 100%;
  border: 1px dashed var(--border-default);
  border-radius: var(--radius-md);
  background: transparent;
  color: var(--text-tertiary);
  font-family: var(--font-family);
  font-size: 13px;
  cursor: pointer;
  transition: all var(--transition-fast);
  margin-top: var(--space-sm);
}

.add-choice-btn:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  background: var(--accent-primary-dim);
}

/* Add Set Button */
.add-set-area {
  display: flex;
  gap: var(--space-sm);
  margin-top: var(--space-lg);
}

.add-set-btn {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-md);
  border: 2px dashed var(--border-default);
  border-radius: var(--radius-lg);
  background: transparent;
  color: var(--text-tertiary);
  font-family: var(--font-family);
  font-size: 13px;
  cursor: pointer;
  transition: all var(--transition-normal);
}

.add-set-btn:hover {
  border-color: var(--accent-primary);
  color: var(--accent-primary);
  background: var(--accent-primary-dim);
  transform: translateY(-2px);
}

/* ====== Modal ====== */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
  animation: fadeIn var(--transition-fast);
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.modal {
  background: var(--bg-secondary);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-xl);
  width: 90%;
  max-width: 560px;
  box-shadow: var(--shadow-lg);
  animation: slideUp var(--transition-normal);
}

@keyframes slideUp {
  from { transform: translateY(20px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

.modal__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-lg) var(--space-xl);
  border-bottom: 1px solid var(--border-default);
}

.modal__header h2 {
  font-size: 16px;
  font-weight: 600;
}

.modal__close {
  width: 32px;
  height: 32px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 20px;
  cursor: pointer;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
}
.modal__close:hover {
  background: var(--surface-1);
  color: var(--text-primary);
}

.modal__body {
  padding: var(--space-xl);
  max-height: 60vh;
  overflow-y: auto;
}

.modal__footer {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-sm);
  padding: var(--space-lg) var(--space-xl);
  border-top: 1px solid var(--border-default);
}

/* ====== Audio Panel (Right Side) ====== */
.audio-panel {
  width: 380px;
  min-width: 380px;
  background: var(--bg-secondary);
  border-left: 1px solid var(--border-default);
  overflow-y: auto;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
}

.audio-panel::-webkit-scrollbar {
  width: 6px;
}
.audio-panel::-webkit-scrollbar-track {
  background: transparent;
}
.audio-panel::-webkit-scrollbar-thumb {
  background: var(--surface-3);
  border-radius: var(--radius-full);
}

/* Player Section */
.audio-player-section {
  padding: var(--space-lg);
  border-bottom: 1px solid var(--border-muted);
}

.audio-player-card {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  margin-bottom: var(--space-md);
}

.audio-player-card__icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, var(--accent-primary-dim), rgba(188, 140, 255, 0.15));
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-primary);
  flex-shrink: 0;
}

.audio-player-card__info {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.audio-player-card__name {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.audio-player-card__duration {
  font-size: 12px;
  color: var(--text-secondary);
}

/* Audio player controls */
.audio-player-section audio {
  width: 100%;
  height: 40px;
  border-radius: var(--radius-md);
  outline: none;
  margin-bottom: var(--space-sm);
}

.audio-replace-btn {
  width: 100%;
  justify-content: center;
}

/* Annotations Section */
.annotations-section {
  flex: 1;
  padding: var(--space-md) var(--space-lg);
  overflow-y: auto;
}

.annotations-section__header {
  margin-bottom: var(--space-md);
}

.annotations-section__title {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* Annotation Card Items */
.annotation-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  padding: var(--space-sm) var(--space-md);
  margin-bottom: var(--space-sm);
  transition: all var(--transition-fast);
}

.annotation-card:hover {
  border-color: var(--border-accent);
  box-shadow: var(--shadow-sm);
}

.annotation-card__top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
  margin-bottom: var(--space-xs);
}

.annotation-card__id {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-tertiary);
}

.annotation-card__label-input {
  width: 100%;
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-family);
  font-size: 13px;
  padding: 3px 6px;
  transition: all var(--transition-fast);
  margin-bottom: var(--space-xs);
}

.annotation-card__label-input:hover {
  border-color: var(--border-default);
}

.annotation-card__label-input:focus {
  outline: none;
  border-color: var(--accent-primary);
  background: var(--surface-1);
}

/* Add Bookmark button */
.add-bookmark-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  border: 1px dashed var(--border-default);
  border-radius: var(--radius-md);
  background: transparent;
  color: var(--text-tertiary);
  font-family: var(--font-family);
  font-size: 12px;
  cursor: pointer;
  transition: all var(--transition-fast);
  margin-top: var(--space-xs);
}

.add-bookmark-btn:hover {
  border-color: var(--accent-purple);
  color: var(--accent-purple);
  background: rgba(188, 140, 255, 0.08);
}

.annotation-card__time-group {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.annotation-card__time-label {
  font-size: 10px;
  color: var(--text-tertiary);
  text-transform: uppercase;
  font-weight: 600;
  letter-spacing: 0.03em;
}

.annotation-card__time-row {
  display: flex;
  align-items: center;
  gap: 2px;
}

.ann-time-input {
  width: 34px;
  background: var(--surface-1);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  font-family: var(--font-family);
  font-size: 12px;
  padding: 3px 2px;
  text-align: center;
  transition: all var(--transition-fast);
  -moz-appearance: textfield;
  appearance: textfield;
}

.ann-time-input--sec {
  width: 52px;
}

.ann-time-input::-webkit-inner-spin-button,
.ann-time-input::-webkit-outer-spin-button {
  -webkit-appearance: none;
  appearance: none;
  margin: 0;
}

.ann-time-input:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 2px var(--accent-primary-dim);
}

.time-sep {
  font-size: 10px;
  color: var(--text-tertiary);
  font-weight: 600;
}

.annotation-card__footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-top: var(--space-xs);
  padding-top: var(--space-xs);
  border-top: 1px solid var(--border-muted);
}

.annotation-card__file {
  font-size: 11px;
  color: var(--text-tertiary);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  max-width: 70%;
}

/* Badges */
.badge {
  display: inline-block;
  padding: 2px 6px;
  border-radius: var(--radius-full);
  font-size: 10px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  background: var(--surface-2);
  color: var(--text-secondary);
}

.badge--blue {
  background: var(--accent-primary-dim);
  color: var(--accent-primary);
}

.badge--purple {
  background: rgba(188, 140, 255, 0.15);
  color: var(--accent-purple);
}

.badge--teal {
  background: rgba(63, 185, 80, 0.15);
  color: var(--accent-success);
}


/* ====== Toast Notification ====== */
.toast {
  position: fixed;
  bottom: 80px;
  right: 24px;
  padding: var(--space-md) var(--space-xl);
  background: var(--bg-elevated);
  border: 1px solid var(--border-default);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 13px;
  box-shadow: var(--shadow-lg);
  z-index: 300;
  animation: toastIn var(--transition-normal) forwards;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.toast.success {
  border-color: var(--accent-success);
}

.toast.error {
  border-color: var(--accent-danger);
}

.toast.hiding {
  animation: toastOut var(--transition-normal) forwards;
}

@keyframes toastIn {
  from { transform: translateY(20px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

@keyframes toastOut {
  from { transform: translateY(0); opacity: 1; }
  to { transform: translateY(20px); opacity: 0; }
}

/* ====== Responsive ====== */
@media (max-width: 768px) {
  :root {
    --sidebar-width: 240px;
  }
  
  .sidebar {
    position: absolute;
    z-index: 50;
    height: calc(100vh - var(--toolbar-height) - var(--audio-bar-height));
    transform: translateX(-100%);
    transition: transform var(--transition-normal);
  }
  
  .sidebar.open {
    transform: translateX(0);
  }
}