/* ==========================================================================
   ZEN SUDOKU — Design System & Stylesheet
   Themes: Midnight Dark (default), Porcelain Light, Matrix Emerald
   ========================================================================== */

:root {
  /* Color Palettes - Midnight Dark */
  --bg-primary: #0a0e17;
  --bg-secondary: #121826;
  --bg-card: rgba(26, 34, 52, 0.7);
  --bg-card-hover: rgba(36, 48, 74, 0.85);
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-strong: rgba(255, 255, 255, 0.18);
  --border-box-thick: #3b82f6;

  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;

  --accent-primary: #38bdf8;
  --accent-secondary: #818cf8;
  --accent-gradient: linear-gradient(135deg, #38bdf8 0%, #818cf8 100%);
  --accent-glow: rgba(56, 189, 248, 0.35);

  --cell-bg: #141c2e;
  --cell-bg-hover: #1e293b;
  --cell-selected: rgba(56, 189, 248, 0.22);
  --cell-peer: rgba(56, 189, 248, 0.07);
  --cell-same: rgba(129, 140, 248, 0.25);
  --cell-error-bg: rgba(239, 68, 68, 0.25);
  --cell-error-text: #f87171;

  --given-num-color: #f1f5f9;
  --input-num-color: #38bdf8;
  --notes-color: #94a3b8;

  --danger-color: #ef4444;
  --success-color: #10b981;
  --warning-color: #f59e0b;

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 24px var(--accent-glow);

  --font-sans: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;
}

[data-theme="light"] {
  --bg-primary: #f1f5f9;
  --bg-secondary: #e2e8f0;
  --bg-card: rgba(255, 255, 255, 0.85);
  --bg-card-hover: #ffffff;
  --border-subtle: rgba(0, 0, 0, 0.08);
  --border-strong: rgba(0, 0, 0, 0.18);
  --border-box-thick: #2563eb;

  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;

  --accent-primary: #2563eb;
  --accent-secondary: #7c3aed;
  --accent-gradient: linear-gradient(135deg, #2563eb 0%, #7c3aed 100%);
  --accent-glow: rgba(37, 99, 235, 0.25);

  --cell-bg: #ffffff;
  --cell-bg-hover: #f8fafc;
  --cell-selected: rgba(37, 99, 235, 0.16);
  --cell-peer: rgba(37, 99, 235, 0.06);
  --cell-same: rgba(124, 58, 237, 0.18);
  --cell-error-bg: rgba(239, 68, 68, 0.15);
  --cell-error-text: #dc2626;

  --given-num-color: #0f172a;
  --input-num-color: #2563eb;
  --notes-color: #64748b;

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.12);
}

[data-theme="emerald"] {
  --bg-primary: #061e16;
  --bg-secondary: #0c2e22;
  --bg-card: rgba(12, 46, 34, 0.75);
  --bg-card-hover: rgba(18, 64, 48, 0.85);
  --border-subtle: rgba(16, 185, 129, 0.15);
  --border-strong: rgba(16, 185, 129, 0.3);
  --border-box-thick: #10b981;

  --text-primary: #ecfdf5;
  --text-secondary: #a7f3d0;
  --text-muted: #6ee7b7;

  --accent-primary: #10b981;
  --accent-secondary: #059669;
  --accent-gradient: linear-gradient(135deg, #10b981 0%, #059669 100%);
  --accent-glow: rgba(16, 185, 129, 0.35);

  --cell-bg: #0a251b;
  --cell-bg-hover: #113628;
  --cell-selected: rgba(16, 185, 129, 0.25);
  --cell-peer: rgba(16, 185, 129, 0.08);
  --cell-same: rgba(52, 211, 153, 0.28);
  --cell-error-bg: rgba(239, 68, 68, 0.25);
  --cell-error-text: #f87171;

  --given-num-color: #f0fdf4;
  --input-num-color: #34d399;
  --notes-color: #6ee7b7;
}

/* Base Resets */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  overflow-x: hidden;
  position: relative;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Background Atmosphere Glow */
body::before {
  content: '';
  position: fixed;
  top: -150px;
  left: 50%;
  transform: translateX(-50%);
  width: 650px;
  height: 400px;
  background: radial-gradient(ellipse at center, var(--accent-glow) 0%, transparent 70%);
  z-index: 0;
  pointer-events: none;
  opacity: 0.6;
}

#confetti-canvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  pointer-events: none;
  z-index: 1000;
}

/* App Layout Container */
.app-container {
  width: 100%;
  max-width: 540px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  padding: 8px 14px 18px;
  position: relative;
  z-index: 1;
}

.game-main {
  width: 100%;
  display: flex;
  flex-direction: column;
}

/* Header */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 0 16px;
  gap: 8px;
  flex-wrap: nowrap;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 8px;
  min-width: 0;
  flex-wrap: nowrap;
  flex-shrink: 0;
}

.btn-exit {
  width: 38px;
  height: 38px;
  min-width: 38px;
  padding: 0;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  background: var(--bg-card);
  color: var(--text-primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  flex-shrink: 0;
}

.btn-exit svg {
  width: 20px;
  height: 20px;
}

.btn-exit:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent-primary);
  color: #ffffff;
  transform: translateY(-1px);
}

.btn-exit:active {
  transform: scale(0.95);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  white-space: nowrap;
  flex-shrink: 0;
}

.brand-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background: var(--accent-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  box-shadow: var(--shadow-glow);
}

.brand-icon svg {
  width: 22px;
  height: 22px;
}

.brand-text h1 {
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: 0.05em;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  line-height: 1.1;
}

.brand-subtitle {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 6px;
}

/* Buttons System */
.btn {
  font-family: var(--font-sans);
  font-weight: 600;
  font-size: 0.9rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-subtle);
  background: var(--bg-card);
  color: var(--text-primary);
  padding: 8px 14px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  box-shadow: var(--shadow-sm);
}

.btn:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-strong);
  transform: translateY(-1px);
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background: var(--accent-gradient);
  border: none;
  color: #ffffff;
  box-shadow: 0 4px 14px var(--accent-glow);
}

.btn-primary:hover {
  filter: brightness(1.1);
  transform: translateY(-1px);
  box-shadow: 0 6px 20px var(--accent-glow);
}

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

.btn-icon {
  width: 38px;
  height: 38px;
  padding: 0;
  border-radius: 50%;
}

.btn-icon svg {
  width: 19px;
  height: 19px;
}

.btn-sm {
  padding: 4px 10px;
  font-size: 0.8rem;
  border-radius: var(--radius-sm);
}

.btn-lg {
  padding: 12px 24px;
  font-size: 1.05rem;
  border-radius: var(--radius-lg);
}

.btn-accent {
  background: var(--accent-primary);
  color: #ffffff;
  border: none;
}

.btn-danger-ghost {
  background: transparent;
  color: var(--danger-color);
  border: 1px solid rgba(239, 68, 68, 0.3);
}

.btn-danger-ghost:hover {
  background: rgba(239, 68, 68, 0.15);
}

/* Dropdown Menu */
.dropdown-wrapper {
  position: relative;
}

.dropdown-menu {
  position: absolute;
  top: calc(100% + 8px);
  right: 0;
  background: var(--bg-secondary);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  min-width: 210px;
  padding: 6px;
  z-index: 100;
  backdrop-filter: blur(16px);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px) scale(0.96);
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

.dropdown-menu.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0) scale(1);
}

.dropdown-item {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 8px 12px;
  background: transparent;
  border: none;
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  cursor: pointer;
  text-align: left;
  transition: background 0.15s ease;
}

.dropdown-item:hover {
  background: var(--bg-card-hover);
}

.dropdown-item.active {
  background: var(--cell-selected);
  border-left: 3px solid var(--accent-primary);
}

.dropdown-item .diff-title {
  font-weight: 700;
  font-size: 0.9rem;
}

.dropdown-item .diff-desc {
  font-size: 0.72rem;
  color: var(--text-muted);
}

.dropdown-divider {
  height: 1px;
  background: var(--border-subtle);
  margin: 6px 0;
}

/* Game Status Bar */
.game-status-bar {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 10px 14px;
  margin-bottom: 12px;
  backdrop-filter: blur(12px);
}

.status-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
}

.status-label {
  font-size: 0.68rem;
  text-transform: uppercase;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

.status-value {
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--text-primary);
}

.status-value.mono {
  font-family: var(--font-mono);
  font-weight: 600;
}

.status-value.highlight {
  color: var(--accent-primary);
}

.timer-wrapper {
  display: flex;
  align-items: center;
  gap: 6px;
}

.btn-pause {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  padding: 2px;
  border-radius: 4px;
  transition: color 0.15s ease;
}

.btn-pause:hover {
  color: var(--text-primary);
}

.btn-pause svg {
  width: 14px;
  height: 14px;
}

/* Hint Banner */
.hint-banner {
  display: flex;
  align-items: center;
  gap: 10px;
  background: rgba(56, 189, 248, 0.15);
  border: 1px solid var(--accent-primary);
  border-radius: var(--radius-md);
  padding: 8px 12px;
  margin-bottom: 12px;
  animation: slideDown 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

.hint-icon {
  color: var(--accent-primary);
  display: flex;
  align-items: center;
}

.hint-icon svg {
  width: 20px;
  height: 20px;
}

.hint-content {
  flex: 1;
  font-size: 0.85rem;
  line-height: 1.35;
  color: var(--text-primary);
}

.btn-close-hint {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 1.25rem;
  cursor: pointer;
  line-height: 1;
}

/* Sudoku Board Wrapper & Grid */
.board-wrapper {
  position: relative;
  width: min(100%, 52vh, 480px);
  aspect-ratio: 1 / 1;
  margin: 0 auto 12px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  border: 2px solid var(--border-box-thick);
}

.sudoku-grid {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  grid-template-rows: repeat(9, 1fr);
  width: 100%;
  height: 100%;
  background: var(--cell-bg);
}

/* Grid cell styling */
.sudoku-cell {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: clamp(1.2rem, 4vw, 1.85rem);
  font-weight: 600;
  cursor: pointer;
  background: var(--cell-bg);
  border-right: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
  transition: background-color 0.15s ease, transform 0.1s ease;
}

/* Thicker border for 3x3 block separation */
.sudoku-cell[data-col="2"],
.sudoku-cell[data-col="5"] {
  border-right: 2px solid var(--border-box-thick);
}

.sudoku-cell[data-row="2"],
.sudoku-cell[data-row="5"] {
  border-bottom: 2px solid var(--border-box-thick);
}

/* Cell States */
.sudoku-cell.given {
  color: var(--given-num-color);
  font-weight: 700;
}

.sudoku-cell.user-input {
  color: var(--input-num-color);
  animation: popIn 0.15s cubic-bezier(0.16, 1, 0.3, 1);
}

.sudoku-cell.highlight-peer {
  background-color: var(--cell-peer);
}

.sudoku-cell.highlight-same {
  background-color: var(--cell-same);
}

.sudoku-cell.selected {
  background-color: var(--cell-selected) !important;
  box-shadow: inset 0 0 0 2px var(--accent-primary);
  z-index: 2;
}

.sudoku-cell.error {
  background-color: var(--cell-error-bg) !important;
  color: var(--cell-error-text) !important;
  animation: shake 0.3s cubic-bezier(0.36, 0.07, 0.19, 0.97);
}

.sudoku-cell.hint-target {
  background-color: rgba(245, 158, 11, 0.25) !important;
  box-shadow: inset 0 0 0 2px var(--warning-color);
  animation: pulseGlow 1.2s infinite;
}

/* Candidate Notes Mini-Grid */
.notes-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  width: 90%;
  height: 90%;
  pointer-events: none;
}

.note-num {
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: clamp(0.55rem, 1.6vw, 0.8rem);
  font-weight: 600;
  color: var(--notes-color);
  line-height: 1;
}

/* Pause Overlay */
.pause-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  backdrop-filter: blur(18px);
  background: rgba(10, 14, 23, 0.85);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10;
  transition: opacity 0.2s ease;
}

.pause-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 12px;
  padding: 20px;
}

.pause-icon svg {
  width: 56px;
  height: 56px;
  color: var(--accent-primary);
}

.pause-content h2 {
  font-size: 1.5rem;
  font-weight: 700;
}

.pause-content p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* Game Controls Bar */
.game-controls {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 8px;
  margin-bottom: 14px;
}

.control-btn {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 10px 4px 8px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  cursor: pointer;
  color: var(--text-secondary);
  transition: all 0.15s ease;
}

.control-btn:hover {
  background: var(--bg-card-hover);
  color: var(--text-primary);
  transform: translateY(-1px);
}

.control-btn:active {
  transform: scale(0.95);
}

.control-btn.active {
  background: var(--cell-selected);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

.control-icon {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
}

.control-icon svg {
  width: 22px;
  height: 22px;
}

.control-label {
  font-size: 0.72rem;
  font-weight: 600;
}

.badge-mini {
  position: absolute;
  top: -8px;
  right: -12px;
  font-size: 0.58rem;
  font-weight: 800;
  padding: 1px 4px;
  border-radius: 6px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-strong);
}

.control-btn.active .badge-mini {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
}

/* Keypad (Digits 1-9) */
.game-keypad {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  gap: 6px;
  margin-bottom: 12px;
}

.keypad-btn {
  position: relative;
  aspect-ratio: 1 / 1.35;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  color: var(--text-primary);
  box-shadow: var(--shadow-sm);
  transition: all 0.15s ease;
}

.keypad-btn:hover {
  background: var(--bg-card-hover);
  border-color: var(--accent-primary);
  transform: translateY(-2px);
}

.keypad-btn:active {
  transform: scale(0.94);
}

.keypad-btn.active {
  background: var(--accent-gradient);
  color: #ffffff;
  border-color: transparent;
  box-shadow: 0 4px 12px var(--accent-glow);
}

.keypad-btn.completed {
  opacity: 0.3;
  cursor: default;
  pointer-events: none;
}

.key-digit {
  font-family: var(--font-mono);
  font-size: clamp(1.2rem, 3.5vw, 1.5rem);
  font-weight: 700;
  line-height: 1;
}

.key-count {
  font-size: 0.68rem;
  font-weight: 600;
  color: var(--text-muted);
  margin-top: 4px;
}

.keypad-btn.active .key-count {
  color: rgba(255, 255, 255, 0.85);
}

/* Secondary Mode & Action Bar */
.input-mode-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 4px 2px;
}

.mode-toggle {
  display: flex;
  align-items: center;
  gap: 6px;
}

.mode-label {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
}

.btn-pill {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: 20px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-pill.active {
  background: var(--cell-selected);
  border-color: var(--accent-primary);
  color: var(--accent-primary);
}

.btn-text-action {
  font-family: var(--font-sans);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-muted);
  background: transparent;
  border: none;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 5px;
  transition: color 0.15s ease;
}

.btn-text-action svg {
  width: 14px;
  height: 14px;
}

.btn-text-action:hover {
  color: var(--text-primary);
}

/* MODALS */
.modal-backdrop {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
  padding: 16px;
  animation: fadeIn 0.2s ease;
}

.modal-card {
  width: 100%;
  max-width: 440px;
  background: var(--bg-secondary);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-lg);
  padding: 24px;
  position: relative;
  animation: scaleUp 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-card.modal-lg {
  max-width: 520px;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.modal-header h2 {
  font-size: 1.35rem;
  font-weight: 700;
}

.modal-close {
  background: transparent;
  border: none;
  font-size: 1.5rem;
  color: var(--text-muted);
  cursor: pointer;
  line-height: 1;
}

.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  margin-top: 24px;
}

/* Victory Modal Specifics */
.modal-victory-card {
  text-align: center;
}

.trophy-icon {
  font-size: 3.5rem;
  margin-bottom: 8px;
  animation: bounceIn 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.victory-header h2 {
  font-size: 1.7rem;
  font-weight: 800;
  margin-bottom: 4px;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.victory-header .subtitle {
  color: var(--text-secondary);
  font-size: 0.92rem;
  margin-bottom: 20px;
}

.victory-stats-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: 14px;
  margin-bottom: 24px;
}

.vstat-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.vstat-label {
  font-size: 0.72rem;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 600;
}

.vstat-value {
  font-size: 1.3rem;
  font-weight: 800;
}

.vstat-value.mono {
  font-family: var(--font-mono);
}

.vstat-value.highlight {
  color: var(--accent-primary);
}

.modal-actions {
  display: flex;
  justify-content: center;
  gap: 12px;
}

.modal-actions.vertical {
  flex-direction: column;
  margin-top: 20px;
}

/* Settings Modal Specifics */
.settings-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.setting-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-subtle);
}

.setting-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.setting-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.setting-title {
  font-weight: 600;
  font-size: 0.95rem;
}

.setting-desc {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.custom-select {
  font-family: var(--font-sans);
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  padding: 6px 12px;
  font-size: 0.88rem;
  cursor: pointer;
}

/* Toggle Switch */
.toggle-switch {
  position: relative;
  display: inline-block;
  width: 46px;
  height: 26px;
  flex-shrink: 0;
}

.toggle-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--bg-card);
  border: 1px solid var(--border-strong);
  transition: 0.2s;
  border-radius: 34px;
}

.slider:before {
  position: absolute;
  content: "";
  height: 18px;
  width: 18px;
  left: 3px;
  bottom: 3px;
  background-color: var(--text-secondary);
  transition: 0.2s;
  border-radius: 50%;
}

input:checked + .slider {
  background-color: var(--accent-primary);
  border-color: var(--accent-primary);
}

input:checked + .slider:before {
  transform: translateX(20px);
  background-color: #ffffff;
}

/* Career Statistics Modal */
.stats-tabs {
  display: flex;
  gap: 6px;
  overflow-x: auto;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 16px;
}

.stats-tab {
  font-family: var(--font-sans);
  font-size: 0.85rem;
  font-weight: 600;
  background: transparent;
  border: none;
  color: var(--text-muted);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  white-space: nowrap;
  transition: all 0.15s ease;
}

.stats-tab:hover {
  color: var(--text-primary);
}

.stats-tab.active {
  background: var(--cell-selected);
  color: var(--accent-primary);
}

.stats-metric-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.metric-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 14px 10px;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.metric-num {
  font-size: 1.4rem;
  font-weight: 800;
  color: var(--text-primary);
}

.metric-num.mono {
  font-family: var(--font-mono);
}

.metric-label {
  font-size: 0.72rem;
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
}

/* How to Play Rules */
.rules-body {
  display: flex;
  flex-direction: column;
  gap: 18px;
  max-height: 60vh;
  overflow-y: auto;
  padding-right: 6px;
}

.rule-section h3 {
  font-size: 1.05rem;
  margin-bottom: 6px;
  color: var(--accent-primary);
}

.rule-cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}

.rule-card {
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: 12px;
  text-align: center;
}

.rule-card h4 {
  font-size: 0.88rem;
  margin: 6px 0 4px;
}

.rule-card p {
  font-size: 0.76rem;
  color: var(--text-secondary);
}

.shortcuts-list {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px;
  list-style: none;
}

.shortcuts-list li {
  font-size: 0.82rem;
  color: var(--text-secondary);
}

kbd {
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  padding: 2px 6px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--accent-primary);
}

/* Custom Board & Solver */
.custom-body {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.custom-textarea {
  width: 100%;
  font-family: var(--font-mono);
  font-size: 0.88rem;
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  padding: 10px;
  resize: vertical;
}

.custom-actions {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.custom-error {
  color: var(--danger-color);
  font-size: 0.82rem;
}

/* Toast Notifications */
.toast-container {
  position: fixed;
  bottom: 24px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  gap: 8px;
  z-index: 500;
  pointer-events: none;
}

.toast {
  background: var(--bg-secondary);
  border: 1px solid var(--border-strong);
  color: var(--text-primary);
  padding: 10px 18px;
  border-radius: 30px;
  font-size: 0.85rem;
  font-weight: 600;
  box-shadow: var(--shadow-lg);
  animation: toastIn 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  display: flex;
  align-items: center;
  gap: 8px;
}

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

@keyframes scaleUp {
  from { opacity: 0; transform: scale(0.95); }
  to { opacity: 1; transform: scale(1); }
}

@keyframes popIn {
  0% { transform: scale(0.7); }
  60% { transform: scale(1.1); }
  100% { transform: scale(1); }
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-4px); }
  40%, 80% { transform: translateX(4px); }
}

@keyframes pulseGlow {
  0%, 100% { box-shadow: inset 0 0 0 2px var(--warning-color); }
  50% { box-shadow: inset 0 0 0 4px var(--warning-color), 0 0 12px var(--warning-color); }
}

@keyframes slideDown {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes toastIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Utility classes */
.hidden {
  display: none !important;
}

/* Visibility utilities for responsive layout */
.mobile-only {
  display: none !important;
}

.desktop-only {
  display: inline-flex !important;
}

/* Modals Mobile Adaptation */
@media (max-width: 600px) {
  .modal-card {
    max-width: min(94vw, 440px);
    max-height: 88dvh;
    overflow-y: auto;
    padding: 18px 14px;
    border-radius: var(--radius-lg);
  }

  .modal-card.modal-lg {
    max-width: min(94vw, 500px);
  }

  .stats-metric-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 8px;
  }

  .metric-card {
    padding: 10px 6px;
  }

  .metric-num {
    font-size: 1.15rem;
  }
}

/* Media Queries - Mobile Responsive Architecture */
@media (max-width: 540px) {
  .mobile-only {
    display: inline-flex !important;
  }

  .desktop-only {
    display: none !important;
  }

  .app-container {
    padding: 6px 10px 14px;
    width: 100%;
    max-width: 100vw;
    min-height: 100dvh;
    justify-content: flex-start;
  }

  /* Compact header */
  .app-header {
    padding: 4px 0 8px;
  }

  .header-left {
    gap: 6px;
  }

  .btn-exit {
    width: 36px;
    height: 36px;
    min-width: 36px;
    border-radius: var(--radius-sm);
  }

  .btn-exit svg {
    width: 18px;
    height: 18px;
  }

  .brand {
    gap: 6px;
  }

  .brand-icon {
    width: 30px;
    height: 30px;
  }

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

  .brand-text h1 {
    font-size: 1rem;
  }

  .brand-subtitle {
    display: none;
  }

  .btn {
    padding: 6px 10px;
    font-size: 0.82rem;
  }

  .btn-icon {
    width: 36px;
    height: 36px;
    min-width: 36px;
    touch-action: manipulation;
  }

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

  /* Compact Status Bar */
  .game-status-bar {
    padding: 6px 8px;
    gap: 4px;
    border-radius: var(--radius-md);
    margin-bottom: 8px;
  }

  .status-label {
    font-size: 0.62rem;
  }

  .status-value {
    font-size: 0.92rem;
  }

  .btn-pause {
    padding: 6px;
    min-width: 28px;
    min-height: 28px;
  }

  /* Board scaling on mobile */
  .board-wrapper {
    width: min(calc(100vw - 16px), calc(100dvh - 220px), 430px);
    margin: 0 auto 8px;
    border-radius: var(--radius-md);
  }

  .sudoku-cell {
    font-size: clamp(1.1rem, 5.2vw, 1.6rem);
  }

  /* Mobile Controls Bar */
  .game-controls {
    gap: 4px;
    margin-bottom: 8px;
  }

  .control-btn {
    padding: 6px 2px 5px;
    border-radius: var(--radius-sm);
    min-height: 46px;
    touch-action: manipulation;
  }

  .control-icon svg {
    width: 19px;
    height: 19px;
  }

  .control-label {
    font-size: 0.64rem;
  }

  .badge-mini {
    font-size: 0.52rem;
    padding: 0 3px;
    top: -6px;
    right: -10px;
  }

  /* Touch-friendly Keypad */
  .game-keypad {
    gap: 4px;
    margin-bottom: 8px;
  }

  .keypad-btn {
    height: 50px;
    aspect-ratio: auto;
    border-radius: var(--radius-sm);
    touch-action: manipulation;
  }

  .key-digit {
    font-size: 1.3rem;
  }

  .key-count {
    font-size: 0.62rem;
    margin-top: 2px;
  }

  /* Input Mode Bar */
  .input-mode-bar {
    padding: 2px;
  }

  .mode-label {
    font-size: 0.72rem;
  }

  .btn-pill {
    padding: 4px 8px;
    font-size: 0.7rem;
  }

  .btn-text-action {
    font-size: 0.72rem;
  }

  /* Rules & Info */
  .rule-cards {
    grid-template-columns: 1fr;
  }

  .shortcuts-list {
    grid-template-columns: 1fr;
    gap: 6px;
  }
}

/* Mobile Display Adaptive Fit */
@media (max-width: 540px) and (max-height: 870px) {
  body {
    overflow-y: auto;
  }

  .app-container {
    height: auto;
    min-height: 100dvh;
    max-height: none;
    padding: 6px 8px 12px;
    justify-content: flex-start;
  }

  .app-header {
    padding: 2px 0 4px;
    margin-bottom: 2px;
  }

  .game-status-bar {
    padding: 4px 6px;
    margin-bottom: 6px;
  }

  .board-wrapper {
    width: min(calc(100vw - 16px), calc(100dvh - 220px), 410px);
    margin: 0 auto 6px;
  }

  .game-controls {
    margin-bottom: 6px;
  }

  .game-keypad {
    margin-bottom: 6px;
  }

  .keypad-btn {
    height: 44px;
  }
}

/* Fallback for ultra-compact screens (e.g. iPhone SE 667px height) */
@media (max-height: 700px) {
  body {
    overflow-y: auto !important;
  }

  .board-wrapper {
    width: min(calc(100vw - 16px), calc(100dvh - 200px), 340px);
    margin: 0 auto 4px;
  }

  .keypad-btn {
    height: 40px;
  }

  .control-btn {
    min-height: 40px;
    padding: 4px 2px;
  }
}

/* ==========================================================================
   PvP (Player vs Player) Styling System
   ========================================================================== */

.btn-pvp {
  background: linear-gradient(135deg, #f43f5e 0%, #fb923c 100%);
  color: #ffffff;
  border: none;
  font-weight: 700;
  box-shadow: 0 4px 12px rgba(244, 63, 94, 0.35);
}

.btn-pvp:hover {
  filter: brightness(1.1);
  transform: translateY(-1px);
  box-shadow: 0 6px 16px rgba(244, 63, 94, 0.45);
}

.btn-pvp svg {
  width: 16px;
  height: 16px;
}

/* Local Turn Battle HUD */
.pvp-local-hud {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
}

.pvp-player-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 6px 8px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  background: rgba(0, 0, 0, 0.15);
  transition: all 0.2s ease;
}

.pvp-player-card.active {
  background: rgba(255, 255, 255, 0.06);
  transform: scale(1.02);
}

.p1-card.active {
  border-color: #38bdf8;
  box-shadow: 0 0 12px rgba(56, 189, 248, 0.3);
}

.p2-card.active {
  border-color: #f43f5e;
  box-shadow: 0 0 12px rgba(244, 63, 94, 0.3);
}

.pvp-player-header {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.74rem;
  font-weight: 700;
}

.pvp-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  display: inline-block;
}

.p1-dot { background: #38bdf8; }
.p2-dot { background: #f43f5e; }

.pvp-score {
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 800;
  line-height: 1.2;
}

.p1-card .pvp-score { color: #38bdf8; }
.p2-card .pvp-score { color: #f43f5e; }

.pvp-sub {
  font-size: 0.62rem;
  color: var(--text-muted);
}

.pvp-center-clock {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  min-width: 70px;
}

.pvp-turn-label {
  font-size: 0.64rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent-primary);
}

.pvp-shot-clock {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--text-primary);
}

.pvp-shot-clock.urgent {
  color: #ef4444;
  animation: pulseGlow 0.5s infinite;
}

.btn-pvp-exit {
  background: transparent;
  border: 1px solid var(--border-subtle);
  color: var(--text-muted);
  font-size: 0.62rem;
  font-weight: 600;
  padding: 1px 6px;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.btn-pvp-exit:hover {
  color: var(--danger-color);
  border-color: var(--danger-color);
}

/* Online Race HUD */
.pvp-online-hud {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 10px;
  padding: 8px 12px;
}

.pvp-race-item {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.pvp-race-header {
  display: flex;
  justify-content: space-between;
  font-size: 0.72rem;
  font-weight: 700;
}

.pvp-race-header .opponent {
  color: #f43f5e;
}

.pvp-bar-track {
  width: 100%;
  height: 8px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 4px;
  overflow: hidden;
}

.pvp-bar-fill {
  height: 100%;
  transition: width 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}

.my-fill { background: #38bdf8; }
.opp-fill { background: #f43f5e; }

.pvp-vs-badge {
  display: flex;
  flex-direction: column;
  align-items: center;
  font-size: 0.72rem;
  font-weight: 800;
  color: var(--text-muted);
}

/* Cell Ownership in PvP */
.sudoku-cell.cell-p1 {
  color: #38bdf8 !important;
  position: relative;
}

.sudoku-cell.cell-p1::after {
  content: '';
  position: absolute;
  bottom: 3px;
  left: 50%;
  transform: translateX(-50%);
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: #38bdf8;
  box-shadow: 0 0 6px #38bdf8;
}

.sudoku-cell.cell-p2 {
  color: #f43f5e !important;
  position: relative;
}

.sudoku-cell.cell-p2::after {
  content: '';
  position: absolute;
  bottom: 3px;
  left: 50%;
  transform: translateX(-50%);
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: #f43f5e;
  box-shadow: 0 0 6px #f43f5e;
}

/* PvP Modes Selector Modal */
.pvp-modes-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  margin: 10px 0 16px;
}

.pvp-mode-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: border-color 0.2s ease;
}

.pvp-mode-card:hover {
  border-color: var(--border-strong);
}

.pvp-mode-icon {
  font-size: 2.2rem;
  line-height: 1;
}

.pvp-mode-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
}

.pvp-mode-desc {
  font-size: 0.78rem;
  color: var(--text-secondary);
  line-height: 1.35;
  flex: 1;
}

.pvp-mode-settings {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin: 8px 0;
}

.pvp-setting-row {
  display: flex;
  flex-direction: column;
  gap: 3px;
  font-size: 0.72rem;
  color: var(--text-muted);
}

.btn-full {
  width: 100%;
}

.pvp-divider {
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 0.68rem;
  font-weight: 700;
  margin: 6px 0;
}

.pvp-join-box {
  display: flex;
  gap: 6px;
}

.custom-input {
  flex: 1;
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  color: var(--text-primary);
  border-radius: var(--radius-sm);
  padding: 6px 10px;
  font-family: var(--font-mono);
  text-transform: uppercase;
  font-size: 0.85rem;
}

/* Online Lobby */
.lobby-code-box {
  text-align: center;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: 16px 12px;
  margin-bottom: 14px;
}

.lobby-code-label {
  font-size: 0.68rem;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 700;
}

.lobby-code-display {
  font-family: var(--font-mono);
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: 0.15em;
  color: var(--accent-primary);
  margin: 4px 0;
}

.lobby-code-hint {
  font-size: 0.78rem;
  color: var(--text-secondary);
}

.lobby-status-box {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-top: 14px;
}

.loading-spinner {
  width: 14px;
  height: 14px;
  border: 2px solid var(--border-strong);
  border-top-color: var(--accent-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

/* PvP Results */
.pvp-result-scores {
  display: flex;
  align-items: center;
  justify-content: space-around;
  background: var(--bg-card);
  border-radius: var(--radius-md);
  padding: 14px;
  margin-bottom: 20px;
}

.pvp-result-col {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.p1-col h4 { color: #38bdf8; font-size: 1rem; }
.p2-col h4 { color: #f43f5e; font-size: 1rem; }

.pvp-res-score {
  font-family: var(--font-mono);
  font-size: 1.4rem;
  font-weight: 800;
}

.pvp-res-sub {
  font-size: 0.72rem;
  color: var(--text-muted);
}

.pvp-vs-sep {
  font-weight: 800;
  color: var(--text-muted);
  font-size: 0.9rem;
}

@media (max-width: 540px) {
  .pvp-modes-grid {
    grid-template-columns: 1fr;
    gap: 10px;
  }

  .pvp-btn-text {
    display: none;
  }

  .btn-pvp {
    width: 36px;
    height: 36px;
    padding: 0;
    border-radius: 50%;
  }

  .pvp-player-card {
    padding: 4px 6px;
  }

  .pvp-score {
    font-size: 1rem;
  }

  .pvp-shot-clock {
    font-size: 1.1rem;
  }
}

/* Clean Print Styles */
@media print {
  body {
    background: #ffffff !important;
    color: #000000 !important;
  }

  body::before,
  .app-header,
  .game-status-bar,
  .game-controls,
  .game-keypad,
  .input-mode-bar,
  .hint-banner,
  .modal-backdrop,
  #confetti-canvas {
    display: none !important;
  }

  .app-container {
    max-width: 100% !important;
    padding: 0 !important;
  }

  .board-wrapper {
    width: 600px !important;
    height: 600px !important;
    margin: 40px auto !important;
    border: 3px solid #000000 !important;
    box-shadow: none !important;
  }

  .sudoku-cell {
    background: #ffffff !important;
    color: #000000 !important;
    border-right: 1px solid #999999 !important;
    border-bottom: 1px solid #999999 !important;
    font-size: 2rem !important;
  }

  .sudoku-cell[data-col="2"],
  .sudoku-cell[data-col="5"] {
    border-right: 3px solid #000000 !important;
  }

  .sudoku-cell[data-row="2"],
  .sudoku-cell[data-row="5"] {
    border-bottom: 3px solid #000000 !important;
  }

  .notes-grid {
    display: none !important;
  }
}