/* Học Tiếng Trung Mỗi Ngày - Oriental Luxury & Heritage Elegance (Sang Trọng Phương Đông) */

:root {
  --font-sans: 'Plus Jakarta Sans', system-ui, -apple-system, sans-serif;
  --font-serif: 'Playfair Display', Georgia, 'Noto Serif SC', serif;
  --font-chinese: 'Noto Serif SC', 'Noto Sans SC', serif;

  /* Oriental Luxury Colors */
  --oriental-cinnabar: #8B1E1E;
  --oriental-cinnabar-dark: #6E1414;
  --oriental-gold: #C59A3F;
  --oriental-gold-light: #E0C27D;
  --oriental-jade: #1E4D43;
  --oriental-paper: #FAF7F2;
  --oriental-paper-card: #FFFDF9;
  --oriental-ink: #1C1917;
  --oriental-border-gold: rgba(197, 154, 63, 0.35);
}

body {
  font-family: var(--font-sans);
  background-color: #FAF7F2;
  background-image: 
    radial-gradient(at 15% 0%, rgba(139, 30, 30, 0.07) 0px, transparent 50%),
    radial-gradient(at 85% 10%, rgba(197, 154, 63, 0.09) 0px, transparent 50%),
    radial-gradient(at 50% 50%, rgba(30, 77, 67, 0.05) 0px, transparent 50%),
    radial-gradient(at 95% 90%, rgba(139, 30, 30, 0.06) 0px, transparent 55%),
    radial-gradient(at 5% 95%, rgba(197, 154, 63, 0.08) 0px, transparent 50%);
  color: #1C1917;
  min-height: 100vh;
}

.font-serif-luxury {
  font-family: var(--font-serif);
}

.font-hanzi {
  font-family: var(--font-chinese);
}

/* Oriental Luxury Seal Stamp (Ấn Triện Chu Sa) */
.oriental-seal {
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 0.625rem;
  background: linear-gradient(135deg, #8B1E1E 0%, #A52A2A 50%, #6E1414 100%);
  border: 2px solid #D4AF37;
  box-shadow: 0 4px 12px rgba(139, 30, 30, 0.3), inset 0 0 6px rgba(255, 215, 0, 0.35);
  position: relative;
  flex-shrink: 0;
}

.oriental-badge-seal {
  display: inline-flex;
  align-items: center;
  padding: 0.15rem 0.6rem;
  font-size: 0.72rem;
  font-weight: 700;
  border-radius: 9999px;
  background: linear-gradient(135deg, rgba(139, 30, 30, 0.1), rgba(197, 154, 63, 0.18));
  color: #8B1E1E;
  border: 1px solid rgba(197, 154, 63, 0.45);
  letter-spacing: 0.05em;
  font-family: var(--font-chinese);
}

/* Oriental Slogan Top Bar */
.oriental-top-bar {
  background: linear-gradient(to right, #FAF4E8, #FFFBF4, #FAF4E8);
  border-bottom: 1px solid rgba(197, 154, 63, 0.25);
}

/* Glassmorphism with Oriental Silk Warm Tone */
.glass-panel {
  background: rgba(255, 253, 249, 0.94);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-color: rgba(230, 215, 184, 0.85);
}

.glass-card {
  background: #FFFDF9;
  border: 1px solid #EADBCE;
  box-shadow: 0 4px 20px -2px rgba(90, 60, 30, 0.04), 0 2px 6px -1px rgba(90, 60, 30, 0.02);
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.glass-card:hover {
  transform: translateY(-2px);
  border-color: rgba(197, 154, 63, 0.6);
  box-shadow: 0 14px 28px -4px rgba(139, 30, 30, 0.08), 0 6px 12px -2px rgba(197, 154, 63, 0.06);
}

/* Rendering Acceleration & Virtualization */
#tab-radicals, #tab-culture, #tab-dictionary, #tab-chengyu, #tab-grammar {
  content-visibility: auto;
  contain-intrinsic-size: 1px 800px;
}

/* 3D Flashcard Flip */
.perspective-1000 {
  perspective: 1000px;
}

.transform-style-3d {
  transform-style: preserve-3d;
}

.backface-hidden {
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

.rotate-y-180 {
  transform: rotateY(180deg);
}

/* Custom Luxury Oriental Scrollbar */
::-webkit-scrollbar {
  width: 7px;
  height: 7px;
}

::-webkit-scrollbar-track {
  background: #F4EFE6;
}

::-webkit-scrollbar-thumb {
  background: linear-gradient(to bottom, #8B1E1E, #C59A3F, #1E4D43);
  border-radius: 9999px;
}

::-webkit-scrollbar-thumb:hover {
  background: linear-gradient(to bottom, #6E1414, #9E7422, #0F3A32);
}

/* Oriental Luxury Badges */
.badge-oriental-red {
  background: linear-gradient(135deg, rgba(139, 30, 30, 0.12), rgba(139, 30, 30, 0.05));
  color: #8B1E1E;
  border: 1px solid rgba(139, 30, 30, 0.3);
}

.badge-oriental-gold {
  background: linear-gradient(135deg, rgba(197, 154, 63, 0.18), rgba(197, 154, 63, 0.06));
  color: #8E6B1E;
  border: 1px solid rgba(197, 154, 63, 0.4);
}

.badge-oriental-jade {
  background: linear-gradient(135deg, rgba(30, 77, 67, 0.15), rgba(30, 77, 67, 0.05));
  color: #1E4D43;
  border: 1px solid rgba(30, 77, 67, 0.3);
}

/* Pulsing Lantern Glow */
@keyframes orientalGlow {
  0%, 100% { filter: drop-shadow(0 0 8px rgba(197, 154, 63, 0.4)); }
  50% { filter: drop-shadow(0 0 16px rgba(139, 30, 30, 0.5)); }
}

.glow-oriental {
  animation: orientalGlow 3s infinite ease-in-out;
}

/* TianZiGe & MiZiGe Grid for Hanzi Writing (Chỉ Đỏ Chu Sa Hoàng Triều) */
.tianzige-grid {
  background-color: #FFFDF8;
  border: 2px solid rgba(139, 30, 30, 0.4);
  border-radius: 1rem;
  box-shadow: inset 0 0 20px rgba(139, 30, 30, 0.04), 0 4px 14px rgba(139, 69, 19, 0.04);
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

.tianzige-grid::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 0;
  right: 0;
  border-top: 1.5px dashed rgba(139, 30, 30, 0.3);
  pointer-events: none;
}

.tianzige-grid::after {
  content: '';
  position: absolute;
  left: 50%;
  top: 0;
  bottom: 0;
  border-left: 1.5px dashed rgba(139, 30, 30, 0.3);
  pointer-events: none;
}

.mizige-diagonals {
  position: absolute;
  inset: 0;
  background-image: 
    linear-gradient(45deg, transparent 49.5%, rgba(197, 154, 63, 0.2) 50%, transparent 50.5%),
    linear-gradient(-45deg, transparent 49.5%, rgba(197, 154, 63, 0.2) 50%, transparent 50.5%);
  pointer-events: none;
}

/* Interactive Reading Tokens (Phong Cách Thư Quyển Cổ Điển) */
.reading-token-chip {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-end;
  padding: 0.2rem 0.45rem;
  margin: 0.15rem 0.12rem;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  background-color: transparent;
  user-select: none;
  border: 1px solid transparent;
}

.reading-token-chip:hover {
  background-color: #FAF2E6;
  border-color: rgba(197, 154, 63, 0.5);
  box-shadow: 0 4px 10px rgba(139, 30, 30, 0.08);
  transform: translateY(-2px);
}

.reading-token-chip .token-pinyin {
  font-size: 0.72rem;
  line-height: 1;
  color: #8B1E1E;
  font-weight: 600;
  margin-bottom: 2px;
  font-family: var(--font-sans);
}

.reading-token-chip.hide-pinyin .token-pinyin {
  display: none;
}

.reading-token-chip .token-hanzi {
  font-family: var(--font-chinese);
  font-size: var(--reading-font-size, 1.25rem);
  font-weight: 700;
  color: #1C1917;
  line-height: 1.25;
  transition: font-size 0.15s ease;
}

.reading-token-punct {
  display: inline-block;
  font-family: var(--font-chinese);
  font-size: var(--reading-font-size, 1.25rem);
  color: #78716C;
  margin: 0 0.1rem;
  transition: font-size 0.15s ease;
}

/* =========================================================================
   GRAMMAR TREE MINDMAP (SƠ ĐỒ CÂY TƯ DUY NGỮ PHÁP TIẾNG TRUNG)
   ========================================================================= */
.tree-stem-vertical {
  width: 3px;
  background: linear-gradient(to bottom, #C59A3F, #8B1E1E);
  margin: 0 auto;
  border-radius: 9999px;
  position: relative;
}

.tree-stem-vertical::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 50%;
  transform: translateX(-50%);
  width: 9px;
  height: 9px;
  background: #8B1E1E;
  border: 2px solid #C59A3F;
  border-radius: 50%;
}

.tree-branch-container {
  position: relative;
  transition: all 0.3s ease;
}

.tree-branch-header {
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  cursor: pointer;
}

.tree-branch-header:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 25px -4px rgba(139, 30, 30, 0.08), 0 4px 10px -2px rgba(197, 154, 63, 0.06);
}

.tree-sub-branch-leaf {
  position: relative;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  border-left: 3.5px solid #C59A3F !important;
}

.tree-sub-branch-leaf:hover {
  transform: translateY(-2px);
  border-left-color: #8B1E1E !important;
}

.tree-sub-branch-leaf::before {
  content: '';
  position: absolute;
  left: -7px;
  top: 1.25rem;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: #FFFDF9;
  border: 2px solid #C59A3F;
  box-shadow: 0 0 0 2px rgba(197, 154, 63, 0.2);
  transition: all 0.2s ease;
}

.tree-sub-branch-leaf:hover::before {
  background: #8B1E1E;
  border-color: #8B1E1E;
  box-shadow: 0 0 0 3px rgba(139, 30, 30, 0.25);
}

.tree-badge-pulse {
  animation: pulse-subtle 2.5s infinite;
}

@keyframes pulse-subtle {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.85; transform: scale(1.03); }
}

/* =========================================================================
   DARK THEME (PHONG CÁCH HOÀNG GIA PHƯƠNG ĐÔNG HUYỀN BÍ - ORIENTAL MIDNIGHT)
   ========================================================================= */
html.dark {
  color-scheme: dark;
}

html.dark body {
  background-color: #0F141C;
  background-image: 
    radial-gradient(at 15% 0%, rgba(180, 40, 40, 0.15) 0px, transparent 50%),
    radial-gradient(at 85% 10%, rgba(212, 175, 55, 0.12) 0px, transparent 50%),
    radial-gradient(at 50% 50%, rgba(30, 95, 80, 0.1) 0px, transparent 50%),
    radial-gradient(at 95% 90%, rgba(180, 40, 40, 0.12) 0px, transparent 55%),
    radial-gradient(at 5% 95%, rgba(212, 175, 55, 0.1) 0px, transparent 50%);
  color: #E6EDF3;
}

/* Dark Header & Nav */
html.dark header {
  background-color: rgba(22, 27, 34, 0.95);
  border-bottom-color: rgba(48, 54, 61, 0.8);
}

html.dark nav.glass-panel {
  background: rgba(22, 27, 34, 0.95);
  border-bottom-color: rgba(48, 54, 61, 0.8);
}

html.dark .oriental-top-bar {
  background: linear-gradient(to right, #161b22, #1c2128, #161b22);
  border-bottom-color: rgba(212, 175, 55, 0.2);
}

html.dark .glass-card {
  background: #161B22;
  border-color: #30363D;
  color: #E6EDF3;
  box-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.4);
}

html.dark .glass-card:hover {
  border-color: rgba(212, 175, 55, 0.5);
  box-shadow: 0 10px 28px -4px rgba(0, 0, 0, 0.6);
}

/* Text mappings for Dark Mode */
html.dark .text-stone-900,
html.dark .text-slate-900,
html.dark .text-stone-850,
html.dark .text-slate-850 {
  color: #F0F6FC !important;
}

html.dark .text-stone-800,
html.dark .text-slate-800,
html.dark .text-stone-700,
html.dark .text-slate-700 {
  color: #C9D1D9 !important;
}

html.dark .text-stone-600,
html.dark .text-slate-600,
html.dark .text-stone-500,
html.dark .text-slate-500 {
  color: #8B949E !important;
}

html.dark .text-stone-400,
html.dark .text-slate-400 {
  color: #6E7681 !important;
}

/* Background mappings */
html.dark .bg-white,
html.dark .bg-\[\#FFFDF9\],
html.dark .bg-\[\#FAF7F2\],
html.dark .bg-stone-50,
html.dark .bg-slate-50 {
  background-color: #161B22 !important;
}

html.dark .bg-stone-100,
html.dark .bg-slate-100 {
  background-color: #21262D !important;
}

html.dark .border-stone-200,
html.dark .border-amber-200,
html.dark .border-slate-200,
html.dark .border-emerald-200,
html.dark .border-rose-200 {
  border-color: #30363D !important;
}

/* Inputs & Search Bars */
html.dark input[type="text"],
html.dark select,
html.dark textarea {
  background-color: #0D1117 !important;
  color: #F0F6FC !important;
  border-color: #30363D !important;
}

html.dark input::placeholder {
  color: #6E7681 !important;
}

/* Dropdown */
html.dark #searchDropdown,
html.dark #themeDropdownMenu {
  background-color: #161B22 !important;
  border-color: #30363D !important;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.8) !important;
}

/* Modals */
html.dark #readingTocModal .glass-card,
html.dark #writingModal .glass-card,
html.dark #wordModal .glass-card,
html.dark #notebookModal .glass-card,
html.dark #telegramModal .glass-card,
html.dark #lessonDetailModal .glass-card,
html.dark #examResultModal .glass-card,
html.dark #floatingAiChatWindow,
html.dark #supportContactWindow {
  background-color: #161B22 !important;
  border-color: #30363D !important;
  color: #E6EDF3 !important;
}

/* TianZiGe in Dark Mode */
html.dark .tianzige-grid {
  background-color: #0D1117 !important;
  border-color: rgba(212, 175, 55, 0.4) !important;
}

html.dark .mizige-diagonals {
  opacity: 0.3;
}

/* Token chips in Readings */
html.dark .reading-token-chip .token-hanzi {
  color: #F0F6FC;
}

html.dark .reading-token-chip:hover {
  background-color: #21262D;
  border-color: rgba(212, 175, 55, 0.5);
}

/* Scrollbars in Dark Mode */
html.dark ::-webkit-scrollbar-track {
  background: #0D1117;
}

html.dark ::-webkit-scrollbar-thumb {
  background: linear-gradient(to bottom, #A52A2A, #C59A3F, #1E4D43);
}

/* Footer in Dark Mode */
html.dark footer {
  background-color: #0D1117 !important;
  border-top-color: #30363D !important;
}

/* Tooltip callouts */
html.dark #floatingAiTooltip,
html.dark #floatingContactTooltip {
  background-color: rgba(22, 27, 34, 0.95) !important;
  border-color: #30363D !important;
  color: #E6EDF3 !important;
}


/* ==================== WOOD BLOCK PUZZLE (汉语积木) STYLES ==================== */

/* Warm Radiant Maple & Honey Teak Board Panel */
.wood-board-panel {
  background: radial-gradient(circle at 50% 25%, #FFF2DE 0%, #FAD9A6 35%, #E6AC6E 70%, #C97D36 100%);
  border: 7px solid #9C5823;
  border-radius: 28px;
  box-shadow: 
    0 20px 45px rgba(180, 95, 30, 0.22),
    0 8px 18px rgba(0, 0, 0, 0.12),
    inset 0 3px 6px rgba(255, 255, 255, 0.8),
    inset 0 -4px 10px rgba(139, 69, 19, 0.3);
  position: relative;
}

.wood-board-panel::before {
  content: '';
  position: absolute;
  inset: 4px;
  border: 2px dashed rgba(180, 100, 30, 0.35);
  border-radius: 20px;
  pointer-events: none;
}

/* Bright Ivory & Birch Board Grid */
#woodBoardGrid {
  background: linear-gradient(135deg, #FFFDF8 0%, #FFF8EA 45%, #FBF0D8 100%) !important;
  border: 3px solid #D4A373 !important;
  border-radius: 20px !important;
  box-shadow: inset 0 2px 8px rgba(180, 115, 50, 0.12), 0 4px 14px rgba(180, 115, 50, 0.08) !important;
}

/* Crisp, Bright Parchment Wood Cells */
.wood-slot-cell {
  background: #FFFFFF;
  border: 2px dashed rgba(212, 163, 115, 0.65);
  border-radius: 14px;
  box-shadow: inset 1px 1px 4px rgba(180, 115, 50, 0.1), 0 1px 3px rgba(255, 255, 255, 0.9);
  transition: all 0.18s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  cursor: pointer;
  user-select: none;
  touch-action: manipulation;
}

.wood-slot-cell:hover {
  border-color: #F59E0B;
  background: #FFFBEB;
  transform: scale(1.02);
}

/* Highlight Cells where the Selected Piece can be Placed (Tap-to-Place Guide) */
.wood-slot-cell.slot-placeable-hint {
  background: linear-gradient(135deg, #ECFDF5 0%, #D1FAE5 100%) !important;
  border: 2px solid #10B981 !important;
  box-shadow: 0 0 14px rgba(16, 185, 129, 0.45), inset 0 0 8px rgba(16, 185, 129, 0.2) !important;
  transform: scale(1.03);
  animation: pulse-placeable 1.6s infinite ease-in-out;
}

.wood-slot-cell.slot-placeable-hint::after {
  content: '▼';
  position: absolute;
  top: 1px;
  font-size: 8px;
  font-weight: 900;
  color: #059669;
}

@keyframes pulse-placeable {
  0% { transform: scale(1.01); box-shadow: 0 0 8px rgba(16, 185, 129, 0.3); }
  50% { transform: scale(1.04); box-shadow: 0 0 16px rgba(16, 185, 129, 0.65), inset 0 0 10px rgba(16, 185, 129, 0.25); }
  100% { transform: scale(1.01); box-shadow: 0 0 8px rgba(16, 185, 129, 0.3); }
}

/* Hover Valid: Glowing Emerald Ghost */
.wood-slot-cell.slot-hover-valid {
  background: rgba(16, 185, 129, 0.4) !important;
  border: 2px solid #059669 !important;
  box-shadow: 0 0 16px rgba(16, 185, 129, 0.75), inset 0 0 12px rgba(16, 185, 129, 0.35) !important;
  transform: scale(1.04);
  color: #064E3B !important;
}

/* Hover Invalid: Soft Rose Ghost */
.wood-slot-cell.slot-hover-invalid {
  background: rgba(239, 68, 68, 0.3) !important;
  border: 2px solid #DC2626 !important;
  box-shadow: 0 0 14px rgba(239, 68, 68, 0.55), inset 0 0 10px rgba(239, 68, 68, 0.25) !important;
}

/* Wood Block Pieces in Tray */
.wood-piece {
  cursor: grab;
  user-select: none;
  touch-action: none;
  transition: transform 0.18s cubic-bezier(0.34, 1.56, 0.64, 1), box-shadow 0.18s ease, filter 0.18s ease;
}

.wood-piece:active, .wood-piece.is-dragging {
  cursor: grabbing;
  transform: scale(1.08) translateY(-4px);
  z-index: 50;
  filter: brightness(1.08);
  box-shadow: 0 20px 30px rgba(180, 100, 30, 0.35) !important;
}

.wood-piece.is-selected {
  outline: 3px solid #F59E0B;
  outline-offset: 4px;
  transform: scale(1.06) translateY(-3px);
  filter: brightness(1.1);
  box-shadow: 0 0 22px rgba(245, 158, 11, 0.85) !important;
  animation: pulse-selected 1.5s infinite alternate ease-in-out;
}

@keyframes pulse-selected {
  0% { transform: scale(1.04) translateY(-2px); box-shadow: 0 0 16px rgba(245, 158, 11, 0.6); }
  100% { transform: scale(1.08) translateY(-4px); box-shadow: 0 0 26px rgba(245, 158, 11, 0.95); }
}

/* Floating Drag Ghost Following Finger/Mouse */
.wood-floating-ghost {
  position: fixed;
  pointer-events: none;
  z-index: 9999;
  transform: translate(-50%, -50%) scale(1.1);
  opacity: 0.92;
  filter: drop-shadow(0 15px 25px rgba(180, 80, 20, 0.45));
  transition: transform 0.04s ease-out;
}

/* ==================== VIBRANT, LUXURIOUS WOOD COLOR PALETTES ==================== */

/* 1. Cinnabar Red Wood (Đỏ Son Cung Đình) */
.wood-tile-cherry {
  background: linear-gradient(135deg, #FF6B6B 0%, #EE5253 45%, #C0392B 100%);
  border: 2px solid #FFA8A8;
  box-shadow: inset 1.5px 1.5px 3px rgba(255, 255, 255, 0.75), inset -1.5px -1.5px 3px rgba(0, 0, 0, 0.2), 0 5px 12px rgba(192, 57, 43, 0.35);
  color: #FFFFFF !important;
}

/* 2. Imperial Amber Gold (Vàng Hổ Phách Hoàng Kim) */
.wood-tile-amber {
  background: linear-gradient(135deg, #FFF3BF 0%, #FDD835 40%, #FB8C00 100%);
  border: 2px solid #FFF9DB;
  box-shadow: inset 1.5px 1.5px 3px rgba(255, 255, 255, 0.85), inset -1.5px -1.5px 3px rgba(0, 0, 0, 0.15), 0 5px 12px rgba(251, 140, 0, 0.35);
  color: #4E2100 !important;
}

/* 3. Golden Honey Oak (Gỗ Sồi Mật Ong) */
.wood-tile-oak {
  background: linear-gradient(135deg, #FDE68A 0%, #F59E0B 50%, #D97706 100%);
  border: 2px solid #FEF3C7;
  box-shadow: inset 1.5px 1.5px 3px rgba(255, 255, 255, 0.8), inset -1.5px -1.5px 3px rgba(0, 0, 0, 0.2), 0 5px 12px rgba(217, 119, 6, 0.35);
  color: #451A03 !important;
}

/* 4. Emerald Jade Bamboo (Ngọc Bích Trúc Xanh) */
.wood-tile-walnut {
  background: linear-gradient(135deg, #6EE7B7 0%, #10B981 50%, #047857 100%);
  border: 2px solid #A7F3D0;
  box-shadow: inset 1.5px 1.5px 3px rgba(255, 255, 255, 0.8), inset -1.5px -1.5px 3px rgba(0, 0, 0, 0.2), 0 5px 12px rgba(4, 120, 87, 0.35);
  color: #FFFFFF !important;
}

/* 5. Lotus Pink Sandalwood (Gỗ Hồng Đào Liên Hoa) */
.wood-tile-rosewood {
  background: linear-gradient(135deg, #F472B6 0%, #E11D48 50%, #9F1239 100%);
  border: 2px solid #FECDD3;
  box-shadow: inset 1.5px 1.5px 3px rgba(255, 255, 255, 0.8), inset -1.5px -1.5px 3px rgba(0, 0, 0, 0.2), 0 5px 12px rgba(159, 18, 57, 0.35);
  color: #FFFFFF !important;
}

/* 6. Azure Lapis Wood (Gỗ Lam Ngọc Lưu Ly) */
.wood-tile-ebony {
  background: linear-gradient(135deg, #38BDF8 0%, #0284C7 50%, #0369A1 100%);
  border: 2px solid #BAE6FD;
  box-shadow: inset 1.5px 1.5px 3px rgba(255, 255, 255, 0.8), inset -1.5px -1.5px 3px rgba(0, 0, 0, 0.2), 0 5px 12px rgba(3, 105, 161, 0.35);
  color: #FFFFFF !important;
}

/* 3D Laser-Carved Text Typography */
.wood-engraved-text {
  text-shadow: 0 1px 2px rgba(0, 0, 0, 0.28), 0 0 1px rgba(255, 255, 255, 0.5);
  letter-spacing: 0.04em;
  font-weight: 900;
}

/* Polished Bamboo & Cedar Tray Shelf */
.wood-tray-shelf {
  background: linear-gradient(180deg, #FFFDF8 0%, #FEF8ED 50%, #F6E6CE 100%);
  border: 3px solid #D4A373;
  border-radius: 24px;
  box-shadow: 0 12px 28px rgba(180, 115, 50, 0.14), inset 0 2px 6px rgba(255, 255, 255, 0.9);
}

/* ==================== CHINESE MEMORY FLIP CARDS (汉语翻翻卡) STYLES ==================== */

.flip-card {
  perspective: 1000px;
  -webkit-perspective: 1000px;
  user-select: none;
  cursor: pointer;
  aspect-ratio: 3 / 4;
  min-height: 145px;
  max-width: 170px;
  width: 100%;
  margin: 0 auto;
  touch-action: manipulation;
  position: relative;
}

.flip-card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  text-align: center;
  transition: transform 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);
  transform-style: preserve-3d;
  -webkit-transform-style: preserve-3d;
  border-radius: 20px;
}

.flip-card.is-flipped .flip-card-inner,
.flip-card.is-matched .flip-card-inner {
  transform: rotateY(180deg);
  -webkit-transform: rotateY(180deg);
}

.flip-card-face {
  position: absolute !important;
  top: 0 !important;
  left: 0 !important;
  right: 0 !important;
  bottom: 0 !important;
  inset: 0 !important;
  width: 100% !important;
  height: 100% !important;
  margin: 0 !important;
  -webkit-backface-visibility: hidden !important;
  backface-visibility: hidden !important;
  border-radius: 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 0.6rem;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
  transition: all 0.25s ease;
  box-sizing: border-box;
  overflow: hidden;
}

/* Mặt Úp (Facedown - Card Front) - Oriental Imperial Red & Gold Lacquer */
.flip-card-front {
  transform: rotateY(0deg);
  -webkit-transform: rotateY(0deg);
  background: radial-gradient(circle at 50% 30%, #991B1B 0%, #7F1D1D 50%, #450A0A 100%);
  border: 3px solid #F59E0B;
  box-shadow: inset 0 2px 4px rgba(255, 255, 255, 0.35), 0 8px 22px rgba(127, 29, 29, 0.35);
  color: #FEF3C7;
  overflow: hidden;
  z-index: 2;
}

.flip-card-front::before {
  content: '';
  position: absolute;
  inset: 4px;
  border: 1px dashed rgba(245, 158, 11, 0.45);
  border-radius: 14px;
  pointer-events: none;
}

.flip-card:not(.is-flipped):not(.is-matched):hover .flip-card-front {
  transform: translateY(-4px) scale(1.02);
  -webkit-transform: translateY(-4px) scale(1.02);
  border-color: #FBBF24;
  box-shadow: 0 14px 28px rgba(127, 29, 29, 0.45), 0 0 16px rgba(245, 158, 11, 0.4);
}

/* Mặt Ngửa (Revealed - Card Back) - Ivory Pearl & Silk Inlay */
.flip-card-back {
  transform: rotateY(180deg);
  -webkit-transform: rotateY(180deg);
  background: linear-gradient(135deg, #FFFFFF 0%, #FFFDF9 50%, #FEF9EE 100%);
  border: 3px solid #D4A373;
  box-shadow: inset 0 1px 3px rgba(255, 255, 255, 0.9), 0 8px 20px rgba(180, 100, 30, 0.14);
  color: #1C1917;
  justify-content: space-between;
  overflow: hidden;
  z-index: 1;
}

/* Matched State */
.flip-card.is-matched .flip-card-back {
  border-color: #10B981 !important;
  background: linear-gradient(135deg, #F0FDF4 0%, #ECFDF5 100%) !important;
  box-shadow: 0 0 25px rgba(16, 185, 129, 0.55), inset 0 0 12px rgba(16, 185, 129, 0.2) !important;
  cursor: default;
  animation: flip-card-match 0.5s ease-out;
}

.flip-card.is-matched .card-match-badge {
  display: inline-flex !important;
}

/* Wrong Shake State & 2-Second Memorization Countdown */
.flip-card.is-wrong {
  animation: flip-card-shake 0.45s ease-in-out;
}

.flip-card.is-wrong .flip-card-back {
  border-color: #EF4444 !important;
  background: #FEF2F2 !important;
  box-shadow: 0 0 18px rgba(239, 68, 68, 0.4) !important;
  overflow: hidden;
}

.flip-card.is-wrong .flip-card-back::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  height: 4px;
  width: 100%;
  background: linear-gradient(90deg, #EF4444, #F59E0B);
  animation: flip-card-countdown 2s linear forwards;
  border-radius: 0 0 18px 18px;
}

.dark .flip-card.is-wrong .flip-card-back {
  background: #2D1518 !important;
  border-color: #F87171 !important;
  color: #FEE2E2 !important;
}

@keyframes flip-card-countdown {
  from { width: 100%; opacity: 1; }
  to { width: 0%; opacity: 0.3; }
}

@keyframes flip-card-match {
  0% { transform: rotateY(180deg) scale(1); }
  50% { transform: rotateY(180deg) scale(1.08); }
  100% { transform: rotateY(180deg) scale(1); }
}

@keyframes flip-card-shake {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-7px); }
  40%, 80% { transform: translateX(7px); }
}

/* Floating Combo Pill */
.flip-combo-badge {
  background: linear-gradient(135deg, #F59E0B 0%, #D97706 100%);
  box-shadow: 0 0 15px rgba(245, 158, 11, 0.6);
  animation: combo-pulse 1s infinite alternate;
}

@keyframes combo-pulse {
  0% { transform: scale(1); }
  100% { transform: scale(1.08); }
}

/* ---------------- Navigation (grouped) ---------------- */
.no-scrollbar { scrollbar-width: none; -ms-overflow-style: none; }
.no-scrollbar::-webkit-scrollbar { display: none; }

.nav-group {
  color: #44403C;
  border: 1px solid transparent;
  transition: background-color 0.15s ease, color 0.15s ease;
}
.nav-group:hover { color: #8B1E1E; background: #F6EFE5; }
.nav-group.is-active {
  color: #FFFDF9;
  background: linear-gradient(90deg, #8B1E1E 0%, #A52A2A 55%, #B8860B 100%);
  border-color: rgba(252, 211, 77, 0.4);
  box-shadow: 0 4px 10px rgba(69, 10, 10, 0.18);
}

.nav-subtab {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.45rem 0.85rem;
  border-radius: 9999px;
  font-size: 0.8125rem;
  font-weight: 600;
  white-space: nowrap;
  color: #57534E;
  border: 1px solid transparent;
  transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}
.nav-subtab:hover { color: #8B1E1E; background: #FBF5EC; }
.nav-subtab.is-active {
  color: #8B1E1E;
  background: #FDF3F3;
  border-color: rgba(139, 30, 30, 0.35);
}

.nav-group-bottom { color: #78716C; }
.nav-group-bottom.is-active { color: #8B1E1E; }
.nav-group-bottom.is-active svg { stroke-width: 2.5; }

:focus-visible { outline: 2px solid #C59A3F; outline-offset: 2px; }

/* ---------------- Search ---------------- */
.search-option.is-highlighted { background: #FEF3C7; }
input[type="search"]::-webkit-search-cancel-button { display: none; }

/* ---------------- Loading state for lazily rendered tabs ---------------- */
section[aria-busy="true"] { position: relative; min-height: 12rem; }
section[aria-busy="true"]::after {
  content: 'Đang tải dữ liệu...';
  position: absolute;
  inset: 0;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 4rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: #8B1E1E;
  background: rgba(250, 247, 242, 0.7);
  border-radius: 1rem;
}

/* ---------------- Toasts ---------------- */
.toast-item { animation: toast-in 0.2s ease-out; transition: opacity 0.3s ease, transform 0.3s ease; }
.toast-item.toast-leave { opacity: 0; transform: translateY(-6px); }
@keyframes toast-in {
  from { opacity: 0; transform: translateY(-6px); }
  to { opacity: 1; transform: translateY(0); }
}

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

/* Dark mode for the grouped navigation */
.dark .nav-group { color: #D6D3D1; }
.dark .nav-group:hover, .dark .nav-subtab:hover { color: #FCD34D; background: #21262D; }
.dark .nav-subtab { color: #A8A29E; }
.dark .nav-subtab.is-active { color: #FCD34D; background: #2A1F1F; border-color: rgba(252, 211, 77, 0.35); }
.dark .nav-group-bottom { color: #A8A29E; }
.dark .nav-group-bottom.is-active { color: #FCD34D; }
.dark .search-option.is-highlighted { background: #3A2E12; }
.dark section[aria-busy="true"]::after { color: #FCD34D; background: rgba(13, 17, 23, 0.7); }

/* ==========================================================================
   APP MODALS & DIALOGS HIGH-PRIORITY STACKING CONTEXT (z-index: 100)
   Ensures modals always overlay top navbar, side dock, content cards & bottom nav.
   ========================================================================== */
#flipCardLevelModal,
#flipCardVictoryModal,
#woodLevelSelectorModal,
#woodVictoryModal,
#readingTocModal,
#examSelectorModal,
#examResultModal,
#confirmExitTaskModal,
#lessonDetailModal,
#writingModal,
#wordModal,
#authModal,
#vipUpgradeModal,
#notebookModal,
#visitorStatsModal,
#adminDashboardModal,
#convStudioModal,
#platformPolicyModal,
#quickSettingsModal,
#appInstallModal,
#complaintModal,
.app-modal-layer {
  z-index: 100 !important;
}

/* Modal Content Card Centering and Viewport Fitting */
#flipCardLevelModal > div,
#woodLevelSelectorModal > div,
#examSelectorModal > div,
#readingTocModal > div,
#platformPolicyModal > div,
#quickSettingsModal > div,
#appInstallModal > div,
#complaintModal > div {
  max-height: calc(100vh - 3rem) !important;
  margin-top: auto;
  margin-bottom: auto;
}