:root {
  color-scheme: light;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  line-height: 1.5;

  --bg-page: #f4f6f8;
  --bg-panel: #fff;
  --bg-muted: #f3f4f6;
  --bg-player: #f8fafc;
  --bg-input: #fff;
  --bg-result: #f9fafb;
  --bg-secondary-btn: #e5e7eb;
  --bg-chip-correct: #dcfce7;
  --bg-chip-incorrect: #fee2e2;
  --bg-chip-manual: #fef9c3;
  --bg-mark-incorrect: #fef2f2;
  --bg-mark-flagged: #fefce8;
  --bg-mark-tag-incorrect: #fee2e2;
  --bg-mark-tag-flagged: #fef3c7;
  --bg-mark-clear: #ecfdf5;

  --text-primary: #1a1a1a;
  --text-secondary: #555;
  --text-muted: #6b7280;
  --text-status: #444;
  --text-label: #374151;
  --text-secondary-btn: #111;
  --text-mark-clear: #065f46;
  --text-mark-tag-incorrect: #991b1b;
  --text-mark-tag-flagged: #92400e;

  --border-default: #e5e7eb;
  --border-mark-incorrect: #fecaca;
  --border-mark-flagged: #fde68a;

  --accent: #2563eb;
  --accent-strong: #1d4ed8;
  --shadow-panel: 0 1px 4px rgba(0, 0, 0, 0.08);
  --outline-active: #2563eb;
}

:root[data-theme="dark"] {
  color-scheme: dark;

  --bg-page: #0f1419;
  --bg-panel: #1a2332;
  --bg-muted: #243044;
  --bg-player: #151d2b;
  --bg-input: #1a2332;
  --bg-result: #151d2b;
  --bg-secondary-btn: #2d3a4f;
  --bg-chip-correct: #14532d;
  --bg-chip-incorrect: #7f1d1d;
  --bg-chip-manual: #713f12;
  --bg-mark-incorrect: #3f1d1d;
  --bg-mark-flagged: #422006;
  --bg-mark-tag-incorrect: #7f1d1d;
  --bg-mark-tag-flagged: #78350f;
  --bg-mark-clear: #064e3b;

  --text-primary: #e8edf4;
  --text-secondary: #9ca8b8;
  --text-muted: #8b98a8;
  --text-status: #b8c4d4;
  --text-label: #c5d0de;
  --text-secondary-btn: #e8edf4;
  --text-mark-clear: #6ee7b7;
  --text-mark-tag-incorrect: #fecaca;
  --text-mark-tag-flagged: #fde68a;

  --border-default: #2d3a4f;
  --border-mark-incorrect: #991b1b;
  --border-mark-flagged: #b45309;

  --accent: #3b82f6;
  --accent-strong: #60a5fa;
  --shadow-panel: 0 1px 4px rgba(0, 0, 0, 0.35);
  --outline-active: #60a5fa;
}

body {
  margin: 0;
  background: var(--bg-page);
  color: var(--text-primary);
  transition: background-color 0.2s ease, color 0.2s ease;
}

.app {
  max-width: 640px;
  margin: 0 auto;
  padding: 1rem;
}

.app-header {
  margin-bottom: 0.25rem;
}

.header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  flex-shrink: 0;
}

.locale-toggle,
.theme-toggle {
  width: auto;
  margin: 0;
  padding: 0.45rem 0.65rem;
  border-radius: 999px;
  background: var(--bg-secondary-btn);
  color: var(--text-secondary-btn);
  line-height: 1;
  flex-shrink: 0;
}

.locale-toggle {
  min-width: 2.6rem;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.theme-toggle {
  font-size: 1.1rem;
}

.locale-toggle:hover:not(:disabled),
.theme-toggle:hover:not(:disabled) {
  filter: brightness(1.08);
}

.locale-icon,
.theme-icon {
  display: none;
}

:root[data-locale="zh"] .locale-icon-zh,
:root[data-locale="en"] .locale-icon-en {
  display: inline;
}

:root[data-theme="light"] .theme-icon-light,
:root[data-theme="dark"] .theme-icon-dark {
  display: inline;
}

header h1 {
  margin: 0 0 0.25rem;
  font-size: 1.5rem;
}

.disclaimer {
  margin: 0 0 1rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.panel {
  background: var(--bg-panel);
  border-radius: 12px;
  padding: 1rem;
  margin-bottom: 1rem;
  box-shadow: var(--shadow-panel);
  transition: background-color 0.2s ease, box-shadow 0.2s ease;
}

.panel h2 {
  margin: 0 0 0.75rem;
  font-size: 1.1rem;
}

label {
  display: block;
  margin-bottom: 0.75rem;
  font-weight: 600;
}

select,
button,
input[type="file"] {
  display: block;
  width: 100%;
  margin-top: 0.35rem;
  font-size: 1rem;
}

select,
input[type="file"] {
  background: var(--bg-input);
  color: var(--text-primary);
  border: 1px solid var(--border-default);
  border-radius: 8px;
  padding: 0.5rem;
}

button {
  padding: 0.75rem 1rem;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  cursor: pointer;
}

button.secondary {
  background: var(--bg-secondary-btn);
  color: var(--text-secondary-btn);
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.actions {
  display: grid;
  gap: 0.5rem;
}

.hidden {
  display: none !important;
}

[hidden] {
  display: none !important;
}

.word-board {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.5rem;
  margin-bottom: 0.75rem;
}

.word-board.paragraph-mode {
  grid-template-columns: 1fr;
}

.passage-preview {
  margin: 0 0 0.75rem;
  padding: 0.65rem 0.75rem;
  border-radius: 8px;
  background: var(--bg-player);
  border: 1px solid var(--border-default);
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-word;
}

.word-chip.paragraph-sentence {
  font-size: 0.9rem;
  line-height: 1.5;
}

.word-chip {
  padding: 0.5rem 0.6rem;
  border-radius: 8px;
  background: var(--bg-muted);
  font-size: 0.95rem;
}

.word-chip.correct {
  background: var(--bg-chip-correct);
}

.word-chip.incorrect {
  background: var(--bg-chip-incorrect);
}

.word-chip.manual_check {
  background: var(--bg-chip-manual);
}

.word-chip.active-clip {
  outline: 2px solid var(--outline-active);
  outline-offset: 1px;
}

.player-panel {
  margin-bottom: 0.75rem;
  padding: 0.75rem;
  border-radius: 10px;
  background: var(--bg-player);
  border: 1px solid var(--border-default);
}

.player-clip {
  margin: 0;
  font-size: 1.35rem;
  font-weight: 700;
  text-align: center;
}

.player-progress {
  margin: 0.25rem 0 0.75rem;
  font-size: 0.85rem;
  text-align: center;
  color: var(--text-muted);
}

.player-controls {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.player-controls button {
  margin-top: 0;
}

.player-actions-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.player-actions-row button {
  margin-top: 0;
  margin-bottom: 0;
}

.player-action-full {
  width: 100%;
  margin-bottom: 0.5rem;
}

.player-hint {
  margin: 0.25rem 0 0;
  font-size: 0.8rem;
  color: var(--text-muted);
  text-align: center;
}

.speed-row {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.speed-label {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-label);
  flex-shrink: 0;
}

.speed-buttons {
  display: flex;
  gap: 0.35rem;
  flex: 1;
}

.speed-buttons button {
  flex: 1;
  margin-top: 0;
  padding: 0.45rem 0.5rem;
  font-size: 0.9rem;
}

.speed-buttons button.active {
  background: var(--accent-strong);
  color: #fff;
}

.status {
  min-height: 1.25rem;
  font-size: 0.9rem;
  color: var(--text-status);
}

.result {
  white-space: pre-wrap;
  font-size: 0.85rem;
  background: var(--bg-result);
  padding: 0.75rem;
  border-radius: 8px;
  overflow-x: auto;
}

.mark-report {
  margin-top: 0.75rem;
}

.mark-report h3 {
  margin: 0.75rem 0 0.5rem;
  font-size: 0.95rem;
}

.mark-report h3:first-child {
  margin-top: 0;
}

.mark-card {
  border-radius: 8px;
  padding: 0.75rem;
  margin-bottom: 0.5rem;
  font-size: 0.9rem;
}

.mark-card.incorrect {
  background: var(--bg-mark-incorrect);
  border: 1px solid var(--border-mark-incorrect);
}

.mark-card.flagged {
  background: var(--bg-mark-flagged);
  border: 1px solid var(--border-mark-flagged);
}

.mark-card .row {
  margin: 0.2rem 0;
}

.mark-card .label {
  font-weight: 600;
  color: var(--text-label);
}

.mark-card .tag {
  display: inline-block;
  margin-bottom: 0.35rem;
  padding: 0.1rem 0.45rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
  background: var(--bg-mark-tag-incorrect);
  color: var(--text-mark-tag-incorrect);
}

.mark-card.flagged .tag {
  background: var(--bg-mark-tag-flagged);
  color: var(--text-mark-tag-flagged);
}

.mark-all-clear {
  padding: 0.75rem;
  border-radius: 8px;
  background: var(--bg-mark-clear);
  color: var(--text-mark-clear);
  font-size: 0.9rem;
}

.paragraph-overview {
  display: grid;
  gap: 0.65rem;
  margin-bottom: 0.85rem;
  padding: 0.75rem;
  border-radius: 8px;
  border: 1px solid var(--border-default);
  background: var(--bg-input);
}

.paragraph-overview-block {
  min-width: 0;
}

.paragraph-overview-label {
  display: block;
  margin-bottom: 0.35rem;
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
}

.paragraph-overview-text {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.55;
  white-space: pre-wrap;
  word-break: break-word;
}

.mark-read-error {
  background: #dc2626;
  color: #fff;
  padding: 0 0.05em;
  border-radius: 2px;
}

.source-tabs {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.35rem;
  margin-bottom: 0.75rem;
}

.source-tab {
  margin-top: 0;
  background: var(--bg-secondary-btn);
  color: var(--text-secondary-btn);
}

.source-tab.active {
  background: var(--accent-strong);
  color: #fff;
}

.upload-hint {
  margin: 0 0 0.75rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.detected-language-panel {
  margin: 0 0 0.75rem;
  padding: 0.6rem 0.7rem;
  border-radius: 8px;
  border: 1px solid var(--border-default);
  background: var(--bg-player);
}

.detected-language-text {
  margin: 0 0 0.5rem;
  font-size: 0.9rem;
  color: var(--text-label);
}

.detected-language-actions {
  display: flex;
  gap: 0.45rem;
}

.detected-language-actions button {
  margin-top: 0;
  flex: 1;
  font-size: 0.88rem;
  padding: 0.5rem 0.6rem;
}

.detected-language-actions button.active {
  background: var(--accent-strong);
  color: #fff;
}

.upload-dropzone {
  border: 2px dashed var(--border-default);
  border-radius: 12px;
  padding: 1.25rem 1rem;
  margin-bottom: 0.75rem;
  text-align: center;
  background: var(--bg-player);
  transition: border-color 0.15s ease, background-color 0.15s ease;
}

.upload-dropzone.dragover {
  border-color: var(--accent);
  background: var(--bg-muted);
}

.upload-dropzone-title {
  margin: 0 0 0.35rem;
  font-size: 1.1rem;
  font-weight: 700;
}

.upload-dropzone-desc {
  margin: 0 0 0.85rem;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.upload-select-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: auto;
  min-width: 9rem;
  margin: 0 auto;
}

.upload-error {
  margin: 0 0 0.75rem;
  padding: 0.55rem 0.65rem;
  border-radius: 8px;
  background: var(--bg-chip-incorrect);
  color: var(--text-mark-tag-incorrect);
  font-size: 0.9rem;
}

.upload-file-list {
  list-style: none;
  margin: 0 0 0.75rem;
  padding: 0;
}

.upload-file-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.4rem;
  padding: 0.55rem 0.6rem;
  border: 1px solid var(--border-default);
  border-radius: 8px;
  background: var(--bg-muted);
}

.upload-file-item.dragging {
  opacity: 0.55;
}

.upload-drag-handle {
  display: inline-flex;
  flex-shrink: 0;
  color: var(--text-muted);
  cursor: grab;
}

.upload-file-meta {
  flex: 1;
  min-width: 0;
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}

.upload-file-name {
  font-size: 0.92rem;
  font-weight: 600;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.upload-file-size {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.upload-page-range {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  flex-shrink: 0;
}

.upload-page-range input {
  width: 5.6rem;
  margin-top: 0;
  padding: 0.3rem 0.35rem;
  border-radius: 6px;
  border: 1px solid var(--border-default);
  background: var(--bg-input);
  color: var(--text-primary);
  text-align: center;
  font-size: 0.85rem;
}

.upload-page-range input.page-spec-input {
  width: 7.4rem;
}

.mark-dropzone {
  margin-bottom: 0.55rem;
}

.mark-file-name {
  margin: 0.6rem 0 0;
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.upload-remove-btn {
  width: auto;
  margin: 0;
  padding: 0.35rem 0.45rem;
  background: transparent;
  color: var(--text-muted);
  flex-shrink: 0;
}

.upload-remove-btn:hover:not(:disabled) {
  color: var(--text-mark-tag-incorrect);
  background: var(--bg-chip-incorrect);
}

.worksheet-parts {
  margin-top: 0.75rem;
}

.part-label {
  margin: 0 0 0.4rem;
  font-weight: 600;
}

.part-list {
  max-height: 12rem;
  overflow-y: auto;
  border: 1px solid var(--border-default);
  border-radius: 8px;
  padding: 0.4rem;
  margin-bottom: 0.55rem;
  background: var(--bg-input);
}

.part-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  margin: 0;
  padding: 0.35rem 0.25rem;
  border-bottom: 1px solid var(--border-default);
}

.part-row.done-ok {
  background: color-mix(in srgb, #16a34a 18%, transparent);
}

.part-row.done-bad {
  background: color-mix(in srgb, #dc2626 18%, transparent);
}

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

.part-row-left {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  min-width: 0;
}

.part-row-left input[type="radio"],
.part-row-left input[type="checkbox"] {
  margin: 0;
}

.part-score {
  min-width: 2.8rem;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.part-score.done-ok {
  color: #16a34a;
  font-weight: 700;
}

.part-score.done-bad {
  color: #dc2626;
  font-weight: 700;
}

.part-row-title {
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--text-primary);
}

.part-check-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: auto;
  margin-top: 0;
  padding: 0.35rem 0.6rem;
  border-radius: 6px;
  background: var(--bg-secondary-btn);
  color: var(--text-secondary-btn);
  font-size: 0.82rem;
  font-weight: 600;
  flex-shrink: 0;
}

.part-preview-title {
  margin: 0.2rem 0 0.3rem;
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-label);
}

.part-preview-list {
  margin: 0 0 0.45rem;
  padding-left: 1.1rem;
  color: var(--text-secondary);
  font-size: 0.92rem;
  line-height: 1.45;
}

.worksheet-controls {
  display: flex;
  align-items: flex-end;
  gap: 0.45rem;
  margin: 0.2rem 0 0.6rem;
}

.marking-mode-block {
  flex: 1;
  min-width: 0;
}

.marking-mode-header {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  margin-bottom: 0.35rem;
}

.marking-mode-label {
  font-size: 0.86rem;
  font-weight: 600;
  color: var(--text-primary);
}

#practice-panel[data-source="catalog"] #practice-mode-controls {
  display: none !important;
}

.worksheet-mode-btn {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.2rem;
  flex: 1;
  margin-top: 0;
  padding: 0.45rem 0.55rem;
  background: var(--bg-secondary-btn);
  color: var(--text-secondary-btn);
  font-size: 0.86rem;
}

.worksheet-mode-btn-help {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 0.95rem;
  height: 0.95rem;
  border: 1px solid currentColor;
  border-radius: 50%;
  font-size: 0.62rem;
  font-weight: 700;
  line-height: 1;
  opacity: 0.75;
}

.worksheet-mode-btn:hover .worksheet-mode-btn-help,
.worksheet-mode-btn:focus-visible .worksheet-mode-btn-help {
  opacity: 1;
}

.worksheet-mode-btn-tooltip {
  display: none;
  position: absolute;
  left: 50%;
  bottom: calc(100% + 0.4rem);
  transform: translateX(-50%);
  z-index: 20;
  width: max-content;
  max-width: min(16rem, 70vw);
  padding: 0.45rem 0.55rem;
  border: 1px solid var(--border-default);
  border-radius: 8px;
  background: var(--bg-panel);
  color: var(--text-primary);
  font-size: 0.78rem;
  font-weight: 400;
  line-height: 1.35;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.12);
  pointer-events: none;
  text-align: left;
}

.worksheet-mode-btn:hover .worksheet-mode-btn-tooltip,
.worksheet-mode-btn:focus-visible .worksheet-mode-btn-tooltip {
  display: block;
}

#practice-mode-controls.worksheet-controls {
  align-items: stretch;
}

.worksheet-mode-toggle {
  display: flex;
  gap: 0.35rem;
  width: 100%;
}

.worksheet-mode-btn.active {
  background: var(--accent-strong);
  color: #fff;
}

#edit-sequence-btn {
  width: auto;
  margin-top: 0;
  padding: 0.45rem 0.65rem;
  font-size: 0.85rem;
}

.sequence-editor {
  margin: 0 0 0.6rem;
  padding: 0.45rem 0.5rem;
  border: 1px solid var(--border-default);
  border-radius: 8px;
  background: var(--bg-input);
}

.sequence-title {
  margin: 0 0 0.35rem;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.sequence-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.sequence-item {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.3rem 0.2rem;
  border-bottom: 1px solid var(--border-default);
}

.sequence-item:last-child {
  border-bottom: none;
}

.sequence-item.dragging {
  opacity: 0.5;
}

.sequence-text {
  font-size: 0.86rem;
}

.worksheet-part-tabs {
  display: grid;
  gap: 0.35rem;
  margin: 0 0 0.65rem;
}

.worksheet-part-tabs.many {
  display: flex;
  overflow-x: auto;
}

.worksheet-tab {
  margin-top: 0;
  padding: 0.5rem 0.55rem;
  background: var(--bg-secondary-btn);
  color: var(--text-secondary-btn);
  font-size: 0.86rem;
  white-space: nowrap;
}

.worksheet-tab.active {
  background: var(--accent-strong);
  color: #fff;
}

.worksheet-tab.done-ok {
  background: #16a34a;
  color: #fff;
}

.worksheet-tab.done-bad {
  background: #dc2626;
  color: #fff;
}

.worksheet-tab:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.mark-dropzone.mark-upload-locked {
  opacity: 0.55;
  pointer-events: none;
}

#next-part-btn {
  margin: 0 0 0.75rem;
}

.worksheet-parts label > span {
  display: block;
  margin-bottom: 0.35rem;
  font-weight: 600;
}

.part-summary {
  margin: 0.35rem 0 0.75rem;
  font-size: 0.88rem;
  color: var(--text-secondary);
  white-space: pre-wrap;
}

#extract-btn,
#upload-start-btn {
  margin-top: 0.25rem;
}