/* ==========================================================================
   LEARN.CSS — Hệ thống giao diện Lộ trình học bài bản Polylingo
   Thiết kế theo chuẩn UX/UI Pro Max: CẤP → BÀI HỌC → NHÓM 5 TỪ → THẺ TỪ
   Tương thích đa ngôn ngữ zh (Đỏ son/Vàng kim) & en (Navy/Vàng đồng)
   Không tràn ngang 375px, Touch target ≥ 44×44px, Contrast ≥ 4.5:1
   ========================================================================== */

/* --------------------------------------------------------------------------
   0. CẤU HÌNH NỀN TẢNG VÀ BIẾN MÀU
   -------------------------------------------------------------------------- */

:root {
  --learn-max-width: 960px;
  --learn-radius-sm: 8px;
  --learn-radius-md: 14px;
  --learn-radius-lg: 20px;
  --learn-shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
  --learn-shadow-md: 0 6px 20px rgba(0, 0, 0, 0.07);
  --learn-shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.12);
  --learn-font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

.learn-container {
  width: 100%;
  max-width: var(--learn-max-width);
  margin: 0 auto;
  padding: 1.25rem 1rem 3.5rem;
  box-sizing: border-box;
  font-family: var(--learn-font-body);
  font-size: 16px;
  line-height: 1.5;
  color: var(--text, #1f1a17);
  overflow-x: hidden;
}

/* Hiệu ứng mượt mà & Chế độ giảm chuyển động */
*, *::before, *::after {
  box-sizing: border-box;
}

button, input, select, textarea {
  font-family: inherit;
  font-size: 1rem;
}

button:focus-visible, input:focus-visible {
  outline: 2px solid var(--border-focus, var(--accent, #b3261e)) !important;
  outline-offset: 2px !important;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* Nút bấm chuẩn chạm ≥ 44×44px */
.learn-btn-primary, .learn-btn-secondary {
  min-height: 44px;
  min-width: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  border-radius: var(--learn-radius-md);
  font-weight: 600;
  cursor: pointer;
  border: 1px solid transparent;
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  text-decoration: none;
  touch-action: manipulation;
  user-select: none;
}

.learn-btn-primary {
  background: var(--accent, #b3261e);
  color: #ffffff;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.12);
}

.learn-btn-primary:hover:not(:disabled) {
  background: var(--accent-hover, #981f18);
  transform: translateY(-1px);
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.16);
}

.learn-btn-primary:active:not(:disabled) {
  transform: translateY(0);
}

.learn-btn-primary.btn-gold {
  background: linear-gradient(135deg, var(--accent, #b3261e), var(--accent-2, #c9a227));
  color: #ffffff;
  border: 1px solid var(--accent-2, #c9a227);
}

.learn-btn-secondary {
  background: var(--surface, #ffffff);
  color: var(--text, #1f1a17);
  border: 1px solid var(--border, #e6ddce);
}

.learn-btn-secondary:hover:not(:disabled) {
  background: var(--surface-2, #f4efe3);
  border-color: var(--accent, #b3261e);
}

.learn-btn-secondary.active {
  background: var(--accent-light, rgba(179, 38, 30, 0.08));
  border-color: var(--accent, #b3261e);
  color: var(--accent, #b3261e);
}

button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* Spinner tải trang */
.learn-loading {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 4rem 1rem;
  gap: 1rem;
  color: var(--muted, #4b5563);
}

.learn-spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border, #e6ddce);
  border-top-color: var(--accent, #b3261e);
  border-radius: 50%;
  animation: learnSpin 0.8s linear infinite;
}

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

/* --------------------------------------------------------------------------
   1. TRANG CẤP (BẢN ĐỒ LỘ TRÌNH)
   -------------------------------------------------------------------------- */

.learn-header {
  background: var(--surface, #ffffff);
  border: 1px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-lg);
  padding: 1.5rem;
  margin-bottom: 2rem;
  box-shadow: var(--learn-shadow-sm);
}

.learn-header-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.learn-badge-seal {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.learn-seal-char {
  width: 52px;
  height: 52px;
  background: var(--accent, #b3261e);
  color: #ffffff;
  border-radius: var(--learn-radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display, serif);
  font-size: 1.85rem;
  font-weight: bold;
  border: 2px solid var(--accent-2, #c9a227);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  flex-shrink: 0;
}

.learn-title {
  margin: 0;
  font-size: 1.6rem;
  font-weight: 700;
  font-family: var(--font-display, serif);
  color: var(--text, #1f1a17);
  line-height: 1.25;
}

.learn-subtitle {
  margin: 0.35rem 0 0;
  font-size: 0.95rem;
  color: var(--muted, #4b5563);
}

.hardwords-badge {
  background: var(--accent, #b3261e);
  color: #ffffff;
  padding: 0.15rem 0.5rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: bold;
}

/* Thẻ tổng quan các cấp độ */
.level-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.25rem;
  margin-top: 1rem;
}

.level-overview-card {
  background: var(--surface-2, #f4efe3);
  border: 2px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-md);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  cursor: pointer;
  transition: all 0.2s ease;
  position: relative;
}

.level-overview-card:hover:not(.locked) {
  border-color: var(--accent, #b3261e);
  transform: translateY(-2px);
  box-shadow: var(--learn-shadow-md);
}

.level-overview-card.active {
  border-color: var(--accent, #b3261e);
  background: var(--surface, #ffffff);
  box-shadow: 0 0 0 1px var(--accent, #b3261e), var(--learn-shadow-sm);
}

.level-overview-card.locked {
  opacity: 0.65;
  cursor: not-allowed;
  filter: grayscale(0.5);
}

.level-card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.level-tag {
  background: var(--accent-light, rgba(179, 38, 30, 0.08));
  color: var(--accent, #b3261e);
  font-weight: 700;
  font-size: 0.8rem;
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  letter-spacing: 0.03em;
}

.level-lock-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.8rem;
  color: var(--muted, #4b5563);
}

.level-progress-pct {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--accent, #b3261e);
}

.level-card-title {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text, #1f1a17);
}

.level-card-metrics {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--muted, #4b5563);
}

.metrics-sep {
  opacity: 0.4;
}

.metrics-time {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

/* Thanh tiến độ */
.level-progress-wrapper {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.level-progress-text {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  color: var(--muted, #4b5563);
}

.learn-progress-track {
  width: 100%;
  height: 8px;
  background: rgba(0, 0, 0, 0.06);
  border-radius: 999px;
  overflow: hidden;
}

[data-theme="dark"] .learn-progress-track {
  background: rgba(255, 255, 255, 0.1);
}

.learn-progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent, #b3261e), var(--accent-2, #c9a227));
  border-radius: 999px;
  transition: width 0.35s ease;
}

/* 3 từ tiêu biểu */
.level-sample-words {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  padding: 0.65rem 0.75rem;
  background: var(--surface, #ffffff);
  border: 1px dashed var(--border, #e6ddce);
  border-radius: var(--learn-radius-sm);
}

.sample-label {
  font-size: 0.75rem;
  color: var(--muted, #4b5563);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  font-weight: 600;
}

.sample-words-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.sample-word-chip {
  background: var(--surface-2, #f4efe3);
  padding: 0.2rem 0.5rem;
  border-radius: 6px;
  font-size: 0.85rem;
  color: var(--text, #1f1a17);
}

.sample-word-chip small {
  color: var(--muted, #4b5563);
}

.level-card-actions {
  margin-top: auto;
  padding-top: 0.5rem;
}

.level-card-actions button {
  width: 100%;
}

/* Danh sách Chương (Unit) & Bài học */
.learn-unit-block {
  background: var(--surface, #ffffff);
  border: 1px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-lg);
  padding: 1.5rem;
  margin-bottom: 2rem;
  box-shadow: var(--learn-shadow-sm);
}

.unit-banner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  padding-bottom: 1.25rem;
  margin-bottom: 1.5rem;
  border-bottom: 1px solid var(--border, #e6ddce);
}

.unit-banner-decor {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent, #b3261e);
  background: var(--accent-light, rgba(179, 38, 30, 0.08));
  padding: 0.35rem 0.75rem;
  border-radius: 8px;
}

.unit-title {
  margin: 0.25rem 0 0.35rem;
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text, #1f1a17);
}

.unit-theme {
  margin: 0;
  font-size: 0.9rem;
  color: var(--muted, #4b5563);
}

.unit-badge-status {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--muted, #4b5563);
  background: var(--surface-2, #f4efe3);
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
}

/* Lưới bài học */
.unit-lessons-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1.25rem;
}

.lesson-card-item {
  background: var(--surface-2, #f4efe3);
  border: 1px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-md);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  transition: all 0.2s ease;
  cursor: pointer;
}

.lesson-card-item.unlocked:hover,
.lesson-card-item.completed:hover {
  border-color: var(--accent, #b3261e);
  transform: translateY(-2px);
  box-shadow: var(--learn-shadow-md);
}

.lesson-card-item.completed {
  border-left: 4px solid var(--accent, #b3261e);
  background: var(--surface, #ffffff);
}

.lesson-card-item.locked {
  opacity: 0.6;
  cursor: not-allowed;
}

.lesson-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.lesson-order {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--muted, #4b5563);
}

.lesson-stars {
  display: flex;
  gap: 0.15rem;
}

.star-icon {
  color: #d1d5db;
}

.star-icon.earned {
  color: var(--accent-2, #c9a227);
}

.lesson-card-title {
  margin: 0;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text, #1f1a17);
  line-height: 1.35;
}

.lesson-card-theme {
  margin: 0;
  font-size: 0.9rem;
  color: var(--muted, #4b5563);
  line-height: 1.4;
  flex: 1;
}

.lesson-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 0.5rem;
  padding-top: 0.75rem;
  border-top: 1px solid rgba(0, 0, 0, 0.05);
}

.lesson-word-count {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--muted, #4b5563);
}

/* Nút Checkpoint */
.unit-checkpoint-container {
  margin-top: 1.5rem;
  padding-top: 1.25rem;
  border-top: 1px dashed var(--border, #e6ddce);
}

.checkpoint-btn {
  width: 100%;
  min-height: 52px;
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 1.25rem;
  border-radius: var(--learn-radius-md);
  border: 1px solid var(--border, #e6ddce);
  background: var(--surface-2, #f4efe3);
  cursor: pointer;
  transition: all 0.2s ease;
  text-align: left;
}

.checkpoint-btn.ready:hover,
.checkpoint-btn.passed:hover {
  border-color: var(--accent-2, #c9a227);
  transform: translateY(-2px);
  box-shadow: var(--learn-shadow-md);
}

.checkpoint-btn.passed {
  background: rgba(201, 162, 39, 0.08);
  border-color: var(--accent-2, #c9a227);
}

.checkpoint-icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--accent-2, #c9a227);
  color: #ffffff;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.checkpoint-info {
  flex: 1;
}

.checkpoint-title {
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--text, #1f1a17);
}

.checkpoint-desc {
  font-size: 0.85rem;
  color: var(--muted, #4b5563);
  margin-top: 0.15rem;
}

.checkpoint-status-badge {
  font-weight: 700;
  font-size: 0.85rem;
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  background: var(--surface, #ffffff);
  border: 1px solid var(--border, #e6ddce);
  color: var(--text, #1f1a17);
}

/* --------------------------------------------------------------------------
   2. TRANG BÀI (LESSON HUB VIEW)
   -------------------------------------------------------------------------- */

.lesson-hub-screen {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.lesson-hub-header {
  background: var(--surface, #ffffff);
  border: 1px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-lg);
  padding: 1.5rem;
  box-shadow: var(--learn-shadow-sm);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

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

.hub-unit-tag {
  font-size: 0.9rem;
  color: var(--muted, #4b5563);
  font-weight: 600;
}

.hub-title-row {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 1rem;
}

.hub-lesson-title {
  margin: 0;
  font-size: 1.8rem;
  font-weight: 700;
  color: var(--text, #1f1a17);
  line-height: 1.25;
}

.hub-lesson-goal {
  margin: 0.4rem 0 0;
  font-size: 1rem;
  color: var(--muted, #4b5563);
}

.hub-progress-card {
  background: var(--surface-2, #f4efe3);
  border-radius: var(--learn-radius-md);
  padding: 1rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.hub-progress-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.95rem;
  color: var(--text, #1f1a17);
}

/* Thanh công cụ bài học */
.hub-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border, #e6ddce);
}

.hub-filter-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.hub-filter-btn {
  min-height: 44px;
  padding: 0.5rem 1rem;
  border-radius: 999px;
  border: 1px solid var(--border, #e6ddce);
  background: var(--surface, #ffffff);
  color: var(--muted, #4b5563);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.hub-filter-btn:hover {
  border-color: var(--accent, #b3261e);
  color: var(--text, #1f1a17);
}

.hub-filter-btn.active {
  background: var(--accent, #b3261e);
  color: #ffffff;
  border-color: var(--accent, #b3261e);
}

.hub-action-buttons {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

/* Khối từng nhóm 5 từ */
.hub-groups-container {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.vocab-group-card {
  background: var(--surface, #ffffff);
  border: 1px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-lg);
  padding: 1.5rem;
  box-shadow: var(--learn-shadow-sm);
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.vocab-group-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border, #e6ddce);
}

.group-header-info {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.group-title {
  margin: 0;
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text, #1f1a17);
}

.group-status-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  font-size: 0.8rem;
  font-weight: 600;
}

.group-status-pill.done {
  background: rgba(34, 197, 94, 0.12);
  color: #15803d;
}

.group-status-pill.pending {
  background: var(--surface-2, #f4efe3);
  color: var(--muted, #4b5563);
}

/* Lưới thẻ từ thu nhỏ trong nhóm */
.vocab-cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 1rem;
}

.vocab-mini-card {
  background: var(--surface-2, #f4efe3);
  border: 1px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-md);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  cursor: pointer;
  transition: all 0.2s ease;
  position: relative;
}

.vocab-mini-card:hover {
  border-color: var(--accent, #b3261e);
  transform: translateY(-2px);
  box-shadow: var(--learn-shadow-md);
}

.vocab-mini-card.playing {
  border-color: var(--accent, #b3261e);
  background: var(--accent-light, rgba(179, 38, 30, 0.08));
  box-shadow: 0 0 0 2px var(--accent, #b3261e);
}

.mini-card-top {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
}

.mini-card-char {
  font-size: 1.75rem;
  font-weight: 700;
  font-family: var(--font-display, serif);
  color: var(--text, #1f1a17);
  line-height: 1.2;
}

.mini-card-char.masked {
  color: var(--muted, #4b5563);
  font-family: monospace;
  letter-spacing: 0.2em;
}

.mini-card-badges {
  display: flex;
  gap: 0.35rem;
}

.badge-mistake {
  background: #fee2e2;
  color: #b91c1c;
  font-size: 0.7rem;
  font-weight: 700;
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
}

.badge-learned {
  background: #dcfce7;
  color: #15803d;
  font-size: 0.7rem;
  font-weight: 700;
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
}

.mini-card-pinyin {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--accent, #b3261e);
}

.mini-card-vi {
  font-size: 0.9rem;
  color: var(--muted, #4b5563);
  line-height: 1.35;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
  flex: 1;
}

.mini-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 0.5rem;
  padding-top: 0.5rem;
  border-top: 1px solid rgba(0, 0, 0, 0.05);
}

.mini-card-speak {
  width: 44px;
  height: 44px;
  min-width: 44px;
  min-height: 44px;
  border-radius: 50%;
  border: 1px solid var(--border, #e6ddce);
  background: var(--surface, #ffffff);
  color: var(--text, #1f1a17);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.2s ease;
}

.mini-card-speak:hover {
  background: var(--accent, #b3261e);
  color: #ffffff;
  border-color: var(--accent, #b3261e);
}

.mini-card-open-hint {
  font-size: 0.75rem;
  color: var(--muted, #4b5563);
  font-weight: 600;
}

/* --------------------------------------------------------------------------
   3. 4 BƯỚC MỖI NHÓM (RUNNER VIEW)
   -------------------------------------------------------------------------- */

.learn-runner-screen {
  max-width: 800px;
  margin: 0 auto;
  padding: 1rem 0 3rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.runner-nav-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  background: var(--surface, #ffffff);
  border: 1px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-lg);
  padding: 0.75rem 1.25rem;
  box-shadow: var(--learn-shadow-sm);
}

.runner-exit-btn {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 1px solid var(--border, #e6ddce);
  background: var(--surface-2, #f4efe3);
  color: var(--text, #1f1a17);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.2s ease;
  flex-shrink: 0;
}

.runner-exit-btn:hover {
  background: #fee2e2;
  color: #b91c1c;
  border-color: #fca5a5;
}

.runner-steps-indicator {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.35rem;
  flex: 1;
}

.step-summary-badge {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--accent, #b3261e);
  text-transform: none;
  letter-spacing: 0.03em;
}

.step-dots-row {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  flex-wrap: wrap;
  justify-content: center;
}

.step-badge-item {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--muted, #4b5563);
}

.step-badge-item.active {
  color: var(--accent, #b3261e);
}

.step-badge-item.done {
  color: #15803d;
}

.badge-dot {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--surface-2, #f4efe3);
  border: 1px solid var(--border, #e6ddce);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
}

.step-badge-item.active .badge-dot {
  background: var(--accent, #b3261e);
  color: #ffffff;
  border-color: var(--accent, #b3261e);
}

.step-badge-item.done .badge-dot {
  background: #dcfce7;
  color: #15803d;
  border-color: #86efac;
}

/* Thẻ chung cho từng bước */
.step-card {
  background: var(--surface, #ffffff);
  border: 1px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-lg);
  padding: 2rem;
  box-shadow: var(--learn-shadow-md);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.card-step-badge {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--accent, #b3261e);
  letter-spacing: 0.03em;
}

.card-step-title {
  margin: 0;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text, #1f1a17);
}

.card-step-desc {
  margin: -0.75rem 0 0;
  font-size: 0.95rem;
  color: var(--muted, #4b5563);
}

.step-footer-actions {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border, #e6ddce);
  flex-wrap: wrap;
}

/* BƯỚC 2: GHÉP NGHĨA */
.matching-board-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.25rem;
}

.matching-col {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.match-item-btn {
  min-height: 58px;
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1rem;
  border-radius: var(--learn-radius-md);
  border: 2px solid var(--border, #e6ddce);
  background: var(--surface-2, #f4efe3);
  color: var(--text, #1f1a17);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  user-select: none;
}

.match-item-btn:hover:not(:disabled) {
  border-color: var(--accent, #b3261e);
  transform: translateY(-1px);
}

.match-item-btn.selected {
  border-color: var(--accent, #b3261e);
  background: var(--accent-light, rgba(179, 38, 30, 0.08));
  box-shadow: 0 0 0 2px var(--accent, #b3261e);
}

.match-item-btn.matched {
  background: #dcfce7;
  border-color: #86efac;
  color: #15803d;
  opacity: 0.75;
  cursor: default;
}

.match-char {
  font-size: 1.45rem;
  font-weight: 700;
  font-family: var(--font-display, serif);
}

.match-py {
  font-size: 0.8rem;
  color: var(--muted, #4b5563);
}

.match-item-btn.shake {
  animation: learnShake 0.5s ease-in-out;
  border-color: #ef4444 !important;
  background: #fee2e2 !important;
}

@keyframes learnShake {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-8px); }
  40%, 80% { transform: translateX(8px); }
}

/* BƯỚC 3: LUYỆN TẬP */
.practice-prompt-title {
  margin: 0;
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text, #1f1a17);
}

.practice-display-box {
  background: var(--surface-2, #f4efe3);
  border-radius: var(--learn-radius-md);
  padding: 2rem 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  text-align: center;
}

.practice-target-char {
  font-size: 3rem;
  font-weight: 700;
  font-family: var(--font-display, serif);
  color: var(--text, #1f1a17);
  line-height: 1.1;
}

.practice-target-py {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--accent, #b3261e);
}

.practice-audio-big-btn {
  min-height: 52px;
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.75rem 1.5rem;
  border-radius: 999px;
  background: var(--accent, #b3261e);
  color: #ffffff;
  border: none;
  font-weight: 700;
  font-size: 1.1rem;
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.15);
}

.practice-audio-big-btn:hover {
  background: var(--accent-hover, #981f18);
  transform: scale(1.02);
}

.cloze-sentence {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text, #1f1a17);
  line-height: 1.5;
}

.cloze-meaning {
  font-size: 1rem;
  color: var(--muted, #4b5563);
}

.practice-options-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.learn-btn-option {
  min-height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0.85rem 1.25rem;
  border-radius: var(--learn-radius-md);
  border: 2px solid var(--border, #e6ddce);
  background: var(--surface, #ffffff);
  color: var(--text, #1f1a17);
  font-weight: 600;
  font-size: 1.05rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.learn-btn-option:hover:not(:disabled) {
  border-color: var(--accent, #b3261e);
  background: var(--surface-2, #f4efe3);
}

.learn-btn-option.correct {
  background: #dcfce7 !important;
  border-color: #22c55e !important;
  color: #15803d !important;
}

.learn-btn-option.wrong {
  background: #fee2e2 !important;
  border-color: #ef4444 !important;
  color: #b91c1c !important;
}

.practice-feedback, .warmup-feedback, .typing-feedback {
  padding: 1rem;
  border-radius: var(--learn-radius-md);
  font-size: 1rem;
  font-weight: 600;
}

.practice-feedback.correct, .typing-feedback.correct {
  background: #dcfce7;
  color: #15803d;
  border: 1px solid #86efac;
}

.practice-feedback.wrong, .typing-feedback.wrong {
  background: #fee2e2;
  color: #b91c1c;
  border: 1px solid #fca5a5;
}

.tone-reminder {
  display: block;
  margin-top: 0.35rem;
  font-weight: 500;
  font-size: 0.85rem;
  color: #166534;
}

/* BƯỚC 4: GÕ TỪ */
.typing-prompt-title {
  margin: 0;
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text, #1f1a17);
}

.typing-target-box {
  background: var(--surface-2, #f4efe3);
  border-radius: var(--learn-radius-md);
  padding: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
}

.typing-audio-btn {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.65rem 1.25rem;
  border-radius: 999px;
  background: var(--accent, #b3261e);
  color: #ffffff;
  border: none;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.2s ease;
}

.typing-meaning-prompt {
  font-size: 1.15rem;
  color: var(--text, #1f1a17);
}

.typing-input-wrapper {
  display: flex;
  gap: 0.75rem;
  margin-top: 0.5rem;
}

.typing-text-field {
  flex: 1;
  min-height: 52px;
  padding: 0.75rem 1.25rem;
  border-radius: var(--learn-radius-md);
  border: 2px solid var(--border, #e6ddce);
  background: var(--surface, #ffffff);
  color: var(--text, #1f1a17);
  font-size: 1.15rem;
  font-weight: 600;
  transition: all 0.2s ease;
}

.typing-text-field:focus {
  border-color: var(--accent, #b3261e);
}

.typing-helper-text {
  font-size: 0.85rem;
  color: var(--muted, #4b5563);
  margin: 0.5rem 0 0;
}

/* TỔNG KẾT NHÓM & BÀI HỌC */
.summary-top-badge {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 0.75rem;
}

.summary-icon {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: #dcfce7;
  color: #15803d;
  display: flex;
  align-items: center;
  justify-content: center;
}

.summary-icon.retry-icon {
  background: #fef3c7;
  color: #b45309;
}

.summary-title {
  margin: 0;
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--text, #1f1a17);
}

.summary-desc, .summary-lesson-title {
  margin: 0;
  font-size: 1.05rem;
  color: var(--muted, #4b5563);
}

.summary-metrics-grid, .finish-stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.metric-box {
  background: var(--surface-2, #f4efe3);
  border-radius: var(--learn-radius-md);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 0.35rem;
}

.metric-num {
  font-size: 2rem;
  font-weight: 700;
  color: var(--accent, #b3261e);
}

.metric-label {
  font-size: 0.9rem;
  color: var(--muted, #4b5563);
  font-weight: 600;
}

.summary-mistakes-box {
  background: #fff1f2;
  border: 1px solid #fecdd3;
  border-radius: var(--learn-radius-md);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.mistakes-label {
  font-size: 0.9rem;
  font-weight: 700;
  color: #9f1239;
}

.mistakes-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.mistake-chip {
  background: #ffffff;
  border: 1px solid #fecdd3;
  color: #be123c;
  padding: 0.25rem 0.65rem;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.9rem;
}

.summary-perfect-note {
  background: #f0fdf4;
  border: 1px solid #bbf7d0;
  color: #166534;
  padding: 1rem;
  border-radius: var(--learn-radius-md);
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.summary-actions-row, .finish-actions-row {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 1rem;
}

.finish-stars-anim {
  display: flex;
  gap: 0.5rem;
  justify-content: center;
}

.finish-star {
  font-size: 2.5rem;
  color: #d1d5db;
}

.finish-star.earned {
  color: var(--accent-2, #c9a227);
}

/* --------------------------------------------------------------------------
   4. THẺ TỪ ĐẦY ĐỦ (WORD CARD COMPONENT)
   -------------------------------------------------------------------------- */

.full-word-card {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.word-card-top-hero {
  background: var(--surface-2, #f4efe3);
  border-radius: var(--learn-radius-lg);
  padding: 2rem 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 0.75rem;
}

.word-card-main-char {
  font-size: 4rem;
  font-weight: 700;
  font-family: var(--font-display, serif);
  color: var(--text, #1f1a17);
  line-height: 1.1;
}

.word-card-pinyin-large {
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--accent, #b3261e);
}

.word-card-audio-controls {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  justify-content: center;
  margin: 0.5rem 0;
}

.btn-word-audio {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1.25rem;
  border-radius: 999px;
  border: 1px solid var(--border, #e6ddce);
  background: var(--surface, #ffffff);
  color: var(--text, #1f1a17);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-word-audio:hover {
  background: var(--accent, #b3261e);
  color: #ffffff;
  border-color: var(--accent, #b3261e);
}

.word-card-meta-tags {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  justify-content: center;
}

.badge-pos {
  background: var(--surface, #ffffff);
  border: 1px solid var(--border, #e6ddce);
  color: var(--muted, #4b5563);
  padding: 0.2rem 0.65rem;
  border-radius: 6px;
  font-size: 0.85rem;
  font-weight: 600;
}

.badge-hanviet {
  background: var(--accent-light, rgba(179, 38, 30, 0.08));
  color: var(--accent, #b3261e);
  padding: 0.2rem 0.65rem;
  border-radius: 6px;
  font-size: 0.85rem;
}

.word-card-meaning-text {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text, #1f1a17);
  margin-top: 0.25rem;
}

/* Khối Chiết tự chữ Hán */
.word-card-decomp-block {
  background: var(--surface, #ffffff);
  border: 1px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-md);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.decomp-header {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--accent, #b3261e);
}

.decomp-items-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.decomp-item {
  background: var(--surface-2, #f4efe3);
  border-radius: var(--learn-radius-sm);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.decomp-item-title {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.decomp-char-badge {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent, #b3261e);
  font-family: var(--font-display, serif);
}

.decomp-formula {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text, #1f1a17);
}

.decomp-pill {
  font-size: 0.8rem;
  background: var(--surface, #ffffff);
  border: 1px solid var(--border, #e6ddce);
  padding: 0.15rem 0.5rem;
  border-radius: 999px;
  color: var(--muted, #4b5563);
}

.decomp-parts-sublist {
  margin: 0;
  padding-left: 1.25rem;
  font-size: 0.95rem;
  color: var(--text, #1f1a17);
  line-height: 1.5;
}

.decomp-mnemonic {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.95rem;
  color: var(--text, #1f1a17);
  background: var(--surface, #ffffff);
  border: 1px dashed var(--border, #e6ddce);
  padding: 0.65rem 0.85rem;
  border-radius: 6px;
}

.decomp-mnemonic svg,
.note-label svg {
  flex-shrink: 0;
  color: #d97706;
}

/* Khối ví dụ ruby pinyin */
.word-card-example-block {
  background: var(--surface, #ffffff);
  border: 1px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-md);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.example-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.example-title {
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--accent, #b3261e);
}

.btn-speak-sentence {
  min-height: 38px;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.4rem 0.85rem;
  border-radius: 999px;
  border: 1px solid var(--border, #e6ddce);
  background: var(--surface-2, #f4efe3);
  color: var(--text, #1f1a17);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-speak-sentence:hover {
  background: var(--accent, #b3261e);
  color: #ffffff;
  border-color: var(--accent, #b3261e);
}

/* Thẻ ruby pinyin */
.example-ruby-text {
  font-size: 1.4rem;
  line-height: 2.2;
  color: var(--text, #1f1a17);
  font-family: var(--font-display, serif);
}

ruby {
  ruby-position: over;
  padding: 0 0.1em;
}

rt {
  font-size: 0.55em;
  color: var(--muted, #4b5563);
  font-family: var(--learn-font-body);
  font-weight: 600;
  line-height: 1;
}

.example-vi {
  font-size: 1rem;
  color: var(--muted, #4b5563);
  line-height: 1.45;
}

.extra-examples-wrapper {
  margin-top: 0.5rem;
  padding-top: 0.75rem;
  border-top: 1px dashed var(--border, #e6ddce);
}

.btn-toggle-extra-examples {
  background: none;
  border: none;
  color: var(--accent, #b3261e);
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  padding: 0.25rem 0;
}

.extra-examples-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 0.75rem;
}

.extra-ex-item {
  background: var(--surface-2, #f4efe3);
  padding: 0.85rem;
  border-radius: var(--learn-radius-sm);
  position: relative;
}

.extra-ex-zh {
  font-size: 1.15rem;
  line-height: 2;
  color: var(--text, #1f1a17);
}

.extra-ex-vi {
  font-size: 0.9rem;
  color: var(--muted, #4b5563);
}

/* Ghi chú thẻ từ */
.word-card-note-block {
  background: #fffbeb;
  border: 1px solid #fde68a;
  border-radius: var(--learn-radius-md);
  padding: 1.25rem;
  color: #92400e;
}

.note-label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 0.25rem;
}

.note-body {
  font-size: 0.95rem;
  line-height: 1.45;
}

/* Nút lưu thẻ ôn */
.word-card-bottom-bar {
  display: flex;
  justify-content: center;
  padding-top: 0.5rem;
}

.btn-bookmark-card {
  min-height: 48px;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.65rem 1.5rem;
  border-radius: 999px;
  border: 1px solid var(--border, #e6ddce);
  background: var(--surface, #ffffff);
  color: var(--text, #1f1a17);
  font-weight: 700;
  font-size: 1rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.btn-bookmark-card:hover {
  border-color: var(--accent-2, #c9a227);
  background: var(--surface-2, #f4efe3);
}

.btn-bookmark-card.saved {
  background: #dcfce7;
  color: #15803d;
  border-color: #86efac;
}

/* Modal Popup Sổ từ & Thẻ từ */
.learn-modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.55);
  backdrop-filter: blur(4px);
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  box-sizing: border-box;
}

.learn-modal-card {
  background: var(--surface, #ffffff);
  border: 1px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-lg);
  max-width: 600px;
  width: 100%;
  max-height: 90vh;
  display: flex;
  flex-direction: column;
  box-shadow: var(--learn-shadow-lg);
  overflow: hidden;
}

.modal-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border, #e6ddce);
}

.modal-card-header h3 {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.modal-close-btn {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: none;
  background: var(--surface-2, #f4efe3);
  color: var(--text, #1f1a17);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.2s ease;
}

.modal-close-btn:hover {
  background: #fee2e2;
  color: #b91c1c;
}

.modal-card-body {
  padding: 1.5rem;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}

/* Sổ từ hay nhầm */
.hardwords-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 1rem;
}

.hardword-item-card {
  background: var(--surface-2, #f4efe3);
  border: 1px solid var(--border, #e6ddce);
  border-radius: var(--learn-radius-md);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
}

.hw-char {
  font-size: 1.85rem;
  font-weight: 700;
  color: var(--text, #1f1a17);
  font-family: var(--font-display, serif);
}

.hw-py {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--accent, #b3261e);
}

.hw-vi {
  font-size: 0.85rem;
  color: var(--muted, #4b5563);
}

.hw-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 0.5rem;
  padding-top: 0.5rem;
  border-top: 1px solid rgba(0, 0, 0, 0.05);
}

.hw-count {
  font-size: 0.75rem;
  font-weight: 700;
  color: #b91c1c;
}

.hw-speak-btn {
  width: 44px;
  height: 44px;
  min-width: 44px;
  min-height: 44px;
  border-radius: 50%;
  border: 1px solid var(--border, #e6ddce);
  background: var(--surface, #ffffff);
  color: var(--text, #1f1a17);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

/* --------------------------------------------------------------------------
   5. RESPONSIVE MÀN HÌNH DI ĐỘNG (375PX KHÔNG TRÀN NGANG)
   -------------------------------------------------------------------------- */

@media (max-width: 640px) {
  .learn-container {
    padding: 0.75rem 0.75rem 3rem;
  }

  .learn-header, .learn-unit-block, .lesson-hub-header, .vocab-group-card, .step-card {
    padding: 1rem;
    border-radius: var(--learn-radius-md);
  }

  .learn-title, .hub-lesson-title {
    font-size: 1.4rem;
  }

  .level-cards-grid, .unit-lessons-grid {
    grid-template-columns: 1fr;
  }

  .vocab-cards-grid {
    grid-template-columns: 1fr 1fr;
    gap: 0.75rem;
  }

  .matching-board-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .practice-options-grid {
    grid-template-columns: 1fr;
  }

  .word-card-main-char {
    font-size: 3rem;
  }

  .word-card-audio-controls {
    flex-direction: column;
    width: 100%;
  }

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

  .hub-toolbar {
    flex-direction: column;
    align-items: stretch;
  }

  .hub-action-buttons {
    width: 100%;
  }

  .hub-action-buttons button {
    flex: 1;
  }

  .summary-metrics-grid, .finish-stats-grid {
    grid-template-columns: 1fr;
  }

  .summary-actions-row, .finish-actions-row {
    flex-direction: column;
    width: 100%;
  }

  .summary-actions-row button, .summary-actions-row a,
  .finish-actions-row button, .finish-actions-row a {
    width: 100%;
  }

  .step-footer-actions {
    flex-direction: column;
    width: 100%;
  }

  .step-footer-actions button {
    width: 100%;
  }
}