/* =========================================================================
   Sudoku SB — Stylesheet
   Mobile-first, premium, calm. Deep purple / soft cream / gold / navy /
   green / soft red palette. Supports Light & Dark modes plus accessibility
   toggles (large text, high contrast, reduced animation).
   ========================================================================= */

:root {
  --purple-900: #241148;
  --purple-800: #2b1a5e;
  --purple-700: #3d2472;
  --purple-600: #4f2f96;
  --purple-500: #6c3fc9;
  --gold-500: #e8b84b;
  --gold-400: #f3cd6e;
  --cream-100: #fbf7ef;
  --cream-200: #f4ecdb;
  --white: #ffffff;
  --navy-900: #10142b;
  --navy-800: #171c39;
  --green-500: #2fa870;
  --red-500: #e0605a;
  --red-600: #c94840;

  --bg: var(--cream-100);
  --bg-elevated: var(--white);
  --text-primary: #241a3d;
  --text-secondary: #6a6079;
  --text-inverse: #ffffff;
  --card-shadow: 0 10px 30px rgba(43, 26, 94, 0.12);
  --card-shadow-sm: 0 4px 14px rgba(43, 26, 94, 0.08);
  --border-soft: rgba(43, 26, 94, 0.08);
  --accent: var(--purple-600);
  --accent-strong: var(--purple-700);
  --gold: var(--gold-500);
  --success: var(--green-500);
  --danger: var(--red-500);

  --radius-lg: 22px;
  --radius-md: 16px;
  --radius-sm: 10px;

  --transition-fast: 160ms ease;
  --transition-med: 280ms cubic-bezier(0.22, 1, 0.36, 1);

  --board-given-color: #2c1f4a;
  --board-user-color: var(--purple-600);
  --board-selected: rgba(108, 63, 201, 0.16);
  --board-peer: rgba(108, 63, 201, 0.07);
  --board-match: rgba(232, 184, 75, 0.28);
  --board-error: rgba(224, 96, 90, 0.22);
}

html[data-theme='dark'] {
  --bg: var(--navy-900);
  --bg-elevated: #1c2140;
  --text-primary: #f4ecff;
  --text-secondary: #b6aed1;
  --text-inverse: #1c1235;
  --card-shadow: 0 10px 30px rgba(0, 0, 0, 0.45);
  --card-shadow-sm: 0 4px 14px rgba(0, 0, 0, 0.35);
  --border-soft: rgba(255, 255, 255, 0.08);
  --accent: #8a63e0;
  --accent-strong: #a481f0;
  --board-given-color: #efe8ff;
  --board-user-color: #c9b3ff;
  --board-selected: rgba(138, 99, 224, 0.28);
  --board-peer: rgba(138, 99, 224, 0.14);
  --board-match: rgba(243, 205, 110, 0.22);
  --board-error: rgba(224, 96, 90, 0.3);
}

html.high-contrast {
  --board-selected: rgba(108, 63, 201, 0.32);
  --board-peer: rgba(108, 63, 201, 0.16);
  --border-soft: rgba(0, 0, 0, 0.35);
}
html.high-contrast[data-theme='dark'] {
  --border-soft: rgba(255, 255, 255, 0.35);
  --text-secondary: #ddd4f5;
}
html.high-contrast {
  --text-secondary: #45304f;
}

html.large-text {
  font-size: 19px;
}

html.reduced-motion * {
  animation-duration: 0.001ms !important;
  animation-iteration-count: 1 !important;
  transition-duration: 0.001ms !important;
  scroll-behavior: auto !important;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: 'Segoe UI', system-ui, -apple-system, 'Noto Sans', 'Noto Sans Devanagari', 'Noto Sans Oriya', Roboto, Arial, sans-serif;
  background: var(--bg);
  color: var(--text-primary);
  overflow-x: hidden;
  -webkit-tap-highlight-color: transparent;
  overscroll-behavior-y: none;
}
button {
  font-family: inherit;
  cursor: pointer;
}
select {
  font-family: inherit;
}
h1, h2, h3, p { margin: 0; }
.hidden { display: none !important; }

/* ---------------------------------------------------------------------
   Screens
   --------------------------------------------------------------------- */
.screen {
  display: none;
  min-height: 100dvh;
  min-height: 100vh;
  width: 100%;
  flex-direction: column;
  padding: 18px 18px 28px;
  max-width: 560px;
  margin: 0 auto;
  position: relative;
}
.screen.active { display: flex; }

/* ---------------------------------------------------------------------
   Welcome / Motivation Screen
   --------------------------------------------------------------------- */
.screen-welcome {
  max-width: none;
  padding: 0;
  min-height: 100dvh;
  justify-content: flex-end;
  overflow: hidden;
  background: linear-gradient(180deg, #1b1140 0%, #2b1a5e 45%, #4a2e86 100%);
}
.welcome-bg {
  position: absolute;
  inset: 0;
  overflow: hidden;
  z-index: 0;
}
.welcome-bg .sky {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, #1b1140 0%, #382270 40%, #7a4bb5 70%, #e8b84b 100%);
  opacity: 0.9;
}
.welcome-bg .sun {
  position: absolute;
  left: 50%;
  top: 38%;
  width: 220px;
  height: 220px;
  transform: translate(-50%, -50%);
  border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 230, 170, 0.95) 0%, rgba(243, 205, 110, 0.55) 45%, rgba(243, 205, 110, 0) 72%);
  filter: blur(1px);
  animation: sunPulse 6s ease-in-out infinite;
}
@keyframes sunPulse {
  0%, 100% { opacity: 0.85; transform: translate(-50%, -50%) scale(1); }
  50% { opacity: 1; transform: translate(-50%, -50%) scale(1.05); }
}
.mountains {
  position: absolute;
  left: -5%;
  right: -5%;
  bottom: 0;
  height: 45%;
}
.mountains-back {
  bottom: 8%;
  height: 38%;
  background: linear-gradient(180deg, rgba(58, 34, 100, 0.0), #3a2264 60%);
  clip-path: polygon(0% 100%, 0% 55%, 12% 40%, 24% 58%, 38% 30%, 52% 55%, 66% 35%, 80% 60%, 92% 42%, 100% 58%, 100% 100%);
  opacity: 0.85;
}
.mountains-front {
  height: 32%;
  background: linear-gradient(180deg, rgba(36, 17, 72, 0), #241148 55%);
  clip-path: polygon(0% 100%, 0% 65%, 10% 45%, 22% 62%, 34% 38%, 50% 60%, 64% 40%, 78% 64%, 90% 48%, 100% 62%, 100% 100%);
}
.mind-orbit {
  position: absolute;
  left: 50%;
  top: 22%;
  width: 10px;
  height: 10px;
}
.orbit-dot {
  position: absolute;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--gold-400);
  box-shadow: 0 0 12px 2px rgba(243, 205, 110, 0.7);
  opacity: 0.85;
}
.orbit-dot.d1 { top: -40px; left: -120px; animation: floatDot 7s ease-in-out infinite; }
.orbit-dot.d2 { top: 10px; left: 130px; animation: floatDot 8s ease-in-out infinite 1s; }
.orbit-dot.d3 { top: 80px; left: -80px; animation: floatDot 9s ease-in-out infinite 2s; }
.orbit-dot.d4 { top: 120px; left: 90px; animation: floatDot 6.5s ease-in-out infinite 0.5s; }
@keyframes floatDot {
  0%, 100% { transform: translateY(0); opacity: 0.6; }
  50% { transform: translateY(-16px); opacity: 1; }
}

.welcome-content {
  position: relative;
  z-index: 1;
  padding: 24px 24px calc(28px + env(safe-area-inset-bottom));
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 18px;
}
.brand-title {
  font-size: 44px;
  letter-spacing: 0.5px;
  color: var(--white);
  font-weight: 800;
  text-shadow: 0 4px 24px rgba(0,0,0,0.25);
}
.brand-title span { color: var(--gold-400); }
.brand-sub {
  margin-top: 2px;
  font-size: 15px;
  letter-spacing: 3px;
  text-transform: lowercase;
  color: rgba(255,255,255,0.72);
  font-weight: 400;
}
.motivation-line {
  color: rgba(255,255,255,0.92);
  font-size: 16px;
  min-height: 44px;
  max-width: 380px;
  line-height: 1.5;
  transition: opacity var(--transition-med);
}
.welcome-actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
  width: 100%;
  max-width: 340px;
}
.creator-credit {
  color: rgba(255,255,255,0.65);
  font-size: 12.5px;
  letter-spacing: 0.3px;
}
.creator-credit .heart { color: #ff8fa3; }

/* ---------------------------------------------------------------------
   Buttons
   --------------------------------------------------------------------- */
.btn {
  border: none;
  border-radius: var(--radius-md);
  padding: 15px 22px;
  font-size: 15.5px;
  font-weight: 700;
  letter-spacing: 0.4px;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), opacity var(--transition-fast);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}
.btn:active { transform: scale(0.97); }
.btn-large { width: 100%; padding: 17px 22px; font-size: 16.5px; }
.btn-primary {
  background: linear-gradient(135deg, var(--gold-500), var(--gold-400));
  color: #2b1a04;
  box-shadow: 0 8px 22px rgba(232, 184, 75, 0.35);
}
.btn-secondary {
  background: rgba(255,255,255,0.14);
  color: var(--white);
  border: 1.5px solid rgba(255,255,255,0.4);
  backdrop-filter: blur(6px);
}
html[data-theme='light'] .screen:not(.screen-welcome) .btn-secondary {
  background: var(--purple-600);
  color: var(--white);
  border: none;
  box-shadow: var(--card-shadow-sm);
}
html[data-theme='dark'] .screen:not(.screen-welcome) .btn-secondary {
  background: var(--purple-600);
  color: var(--white);
  border: none;
}
.btn-outline {
  background: var(--bg-elevated);
  color: var(--accent-strong);
  border: 1.5px solid var(--border-soft);
  box-shadow: var(--card-shadow-sm);
}
.btn-ghost {
  background: transparent;
  color: var(--text-secondary);
}
.btn-danger-outline {
  background: transparent;
  border: 1.5px solid var(--red-500);
  color: var(--red-600);
}
.badge {
  background: var(--green-500);
  color: white;
  font-size: 11px;
  padding: 3px 8px;
  border-radius: 999px;
  margin-left: 8px;
}

/* ---------------------------------------------------------------------
   Top bar / navigation
   --------------------------------------------------------------------- */
.top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 0 18px;
}
.icon-btn {
  width: 42px;
  height: 42px;
  border-radius: 14px;
  border: none;
  background: var(--bg-elevated);
  box-shadow: var(--card-shadow-sm);
  font-size: 18px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-primary);
}
.icon-btn-spacer { width: 42px; height: 42px; }
.screen-title { font-size: 18px; font-weight: 700; }
.brand-compact { display: flex; flex-direction: column; align-items: center; }
.brand-title-sm { font-size: 21px; font-weight: 800; color: var(--accent-strong); }
.brand-title-sm span { color: var(--gold-500); }
.brand-sub-sm { font-size: 10.5px; letter-spacing: 2px; color: var(--text-secondary); margin-top: -2px; }

.tagline {
  text-align: center;
  color: var(--text-secondary);
  font-size: 14px;
  margin-bottom: 18px;
  font-weight: 600;
  letter-spacing: 0.3px;
}

/* ---------------------------------------------------------------------
   Home stats + actions
   --------------------------------------------------------------------- */
.stat-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-bottom: 22px;
}
.stat-card {
  background: var(--bg-elevated);
  border-radius: var(--radius-md);
  box-shadow: var(--card-shadow-sm);
  padding: 14px 8px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}
.stat-emoji { font-size: 20px; }
.stat-value { font-size: 19px; font-weight: 800; color: var(--accent-strong); }
.stat-label { font-size: 10.5px; color: var(--text-secondary); text-align: center; }

.home-actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 18px;
}
.home-modes {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  margin-bottom: 22px;
}
.mode-chip {
  background: var(--bg-elevated);
  border: 1px solid var(--border-soft);
  border-radius: 999px;
  padding: 10px 16px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-primary);
  box-shadow: var(--card-shadow-sm);
}
.install-chip {
  display: block;
  margin: 0 auto 18px;
  background: linear-gradient(135deg, var(--gold-500), var(--gold-400));
  color: #2b1a04;
  border: none;
  font-weight: 800;
}
.creator-credit-home {
  text-align: center;
  color: var(--text-secondary);
  margin-top: auto;
  padding-top: 12px;
}
.creator-credit-home .heart { color: var(--red-500); }

/* ---------------------------------------------------------------------
   Difficulty select
   --------------------------------------------------------------------- */
.difficulty-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
.diff-card {
  background: var(--bg-elevated);
  border: none;
  border-radius: var(--radius-md);
  box-shadow: var(--card-shadow-sm);
  padding: 20px 14px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 4px;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
  color: var(--text-primary);
}
.diff-card:active { transform: scale(0.97); }
.diff-name { font-size: 17px; font-weight: 800; color: var(--accent-strong); }
.diff-desc { font-size: 12px; color: var(--text-secondary); }

/* ---------------------------------------------------------------------
   Daily card
   --------------------------------------------------------------------- */
.daily-card {
  background: var(--bg-elevated);
  border-radius: var(--radius-lg);
  box-shadow: var(--card-shadow);
  padding: 26px 22px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 8px;
  margin-top: 12px;
}
.daily-date { color: var(--text-secondary); font-size: 13px; }
.daily-number { font-size: 22px; font-weight: 800; color: var(--accent-strong); }
.daily-diff { font-size: 14px; color: var(--text-primary); text-transform: capitalize; }
.daily-stats-row {
  display: flex;
  gap: 28px;
  margin: 14px 0;
}
.daily-stats-row > div { display: flex; flex-direction: column; align-items: center; gap: 2px; }
.daily-stat-label { font-size: 11px; color: var(--text-secondary); }
.daily-stat-value { font-size: 17px; font-weight: 700; }
.streak-display {
  font-size: 15px;
  font-weight: 700;
  color: var(--gold-500);
  margin-bottom: 8px;
}
.milestone-badge {
  display: inline-block;
  background: linear-gradient(135deg, var(--gold-500), var(--gold-400));
  color: #2b1a04;
  font-weight: 800;
  font-size: 12.5px;
  padding: 6px 16px;
  border-radius: 999px;
  margin-bottom: 14px;
}

/* ---------------------------------------------------------------------
   Game screen
   --------------------------------------------------------------------- */
.game-top-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 0 10px;
}
.game-diff-pill {
  background: var(--bg-elevated);
  border-radius: 999px;
  padding: 8px 18px;
  font-size: 13px;
  font-weight: 700;
  color: var(--accent-strong);
  box-shadow: var(--card-shadow-sm);
  text-transform: capitalize;
}
.game-hud {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-elevated);
  border-radius: var(--radius-md);
  box-shadow: var(--card-shadow-sm);
  padding: 12px 16px;
  margin-bottom: 14px;
  font-weight: 700;
  font-size: 14px;
}
.hud-item { display: flex; align-items: center; gap: 6px; }
#hud-hearts { gap: 3px; font-size: 15px; }
.heart-icon { transition: transform var(--transition-fast); }
.heart-icon.lost { filter: grayscale(1) brightness(0.6); }

.board-wrap {
  display: flex;
  justify-content: center;
  margin-bottom: 16px;
  touch-action: none;
}
.sudoku-board {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  grid-template-rows: repeat(9, 1fr);
  width: min(100%, 520px);
  aspect-ratio: 1 / 1;
  background: var(--bg-elevated);
  border-radius: var(--radius-md);
  box-shadow: var(--card-shadow);
  overflow: hidden;
  border: 2px solid var(--purple-700);
}
html[data-theme='dark'] .sudoku-board { border-color: var(--accent); }

.cell {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: clamp(15px, 4.6vw, 24px);
  font-weight: 700;
  color: var(--board-user-color);
  background: var(--bg-elevated);
  border: 0.5px solid var(--border-soft);
  user-select: none;
  transition: background var(--transition-fast);
}
.cell.given { color: var(--board-given-color); font-weight: 800; }
.cell:nth-child(3n) { border-right-width: 2px; border-right-color: var(--purple-700); }
.cell:nth-child(9n+1) { border-left-width: 2px; border-left-color: var(--purple-700); }
html[data-theme='dark'] .cell:nth-child(3n),
html[data-theme='dark'] .cell:nth-child(9n+1) { border-color: var(--accent); }

.cell.peer { background: var(--board-peer); }
.cell.selected { background: var(--board-selected); }
.cell.match { background: var(--board-match); }
.cell.error { background: var(--board-error); color: var(--red-600); animation: shake 0.35s; }
.cell.hinted { animation: hintPop 0.6s ease; }
@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-4px); }
  75% { transform: translateX(4px); }
}
@keyframes hintPop {
  0% { box-shadow: inset 0 0 0 3px var(--gold-500); }
  100% { box-shadow: inset 0 0 0 0 transparent; }
}
.cell-notes {
  position: absolute;
  inset: 2px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  pointer-events: none;
}
.cell-notes span {
  font-size: clamp(7px, 1.7vw, 10px);
  font-weight: 600;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* row/col highlight added dynamically via .cell rows using nth-child is complex;
   handled via JS-added class 'peer' above, applied per matching row/col/box */

.game-controls {
  margin-top: auto;
}
.control-row {
  display: flex;
  gap: 10px;
  margin-bottom: 14px;
}
.ctrl-btn {
  flex: 1;
  background: var(--bg-elevated);
  border: none;
  border-radius: var(--radius-md);
  box-shadow: var(--card-shadow-sm);
  padding: 12px 8px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  color: var(--text-primary);
  font-size: 12px;
  font-weight: 700;
}
.ctrl-btn.active-toggle {
  background: var(--accent);
  color: var(--white);
}
.ctrl-icon { font-size: 19px; }
.ctrl-btn:disabled { opacity: 0.4; }

.number-pad {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
}
.num-btn {
  background: var(--bg-elevated);
  border: none;
  border-radius: var(--radius-sm);
  box-shadow: var(--card-shadow-sm);
  font-size: 20px;
  font-weight: 800;
  color: var(--accent-strong);
  padding: 14px 0;
  transition: transform var(--transition-fast);
}
.num-btn:active { transform: scale(0.93); }
.num-btn.exhausted { opacity: 0.32; }

/* ---------------------------------------------------------------------
   Overlays (pause, solved, game over, share)
   --------------------------------------------------------------------- */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(20, 12, 40, 0.55);
  backdrop-filter: blur(3px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 20px;
}
/* Share layers on top of Solved/Game Over instead of replacing them, so
   closing it reveals the screen the user shared from. */
#overlay-share { z-index: 110; }
.overlay-card {
  background: var(--bg-elevated);
  border-radius: var(--radius-lg);
  box-shadow: var(--card-shadow);
  padding: 30px 26px;
  max-width: 400px;
  width: 100%;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}
.overlay-card h2 { font-size: 21px; font-weight: 800; margin-top: 4px; }
.overlay-card p { color: var(--text-secondary); font-size: 14px; margin-bottom: 8px; }
.trophy { font-size: 46px; animation: bounceIn 0.6s ease; }
.broken-heart { font-size: 34px; }
@keyframes bounceIn {
  0% { transform: scale(0.4); opacity: 0; }
  60% { transform: scale(1.15); opacity: 1; }
  100% { transform: scale(1); }
}
.overlay-card-celebrate { position: relative; overflow: hidden; }

.result-stats {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  width: 100%;
  margin: 6px 0 12px;
}
.result-stat {
  background: var(--bg);
  border-radius: var(--radius-sm);
  padding: 10px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.result-label { font-size: 10.5px; color: var(--text-secondary); font-weight: 700; letter-spacing: 0.4px; }
.result-value { font-size: 17px; font-weight: 800; color: var(--accent-strong); }

.overlay-actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
  width: 100%;
}

/* Share card */
.share-card {
  background: linear-gradient(160deg, var(--purple-800), var(--purple-600));
  color: white;
  border-radius: var(--radius-md);
  padding: 22px;
  width: 100%;
  margin-bottom: 16px;
  text-align: left;
}
.share-title { font-weight: 800; letter-spacing: 1.5px; font-size: 16px; color: var(--gold-400); }
.share-line { margin: 6px 0 0; font-size: 14px; color: white; }
.share-sub { margin-top: 10px; font-size: 11px; letter-spacing: 2px; color: rgba(255,255,255,0.7); }
.share-footer { margin-top: 4px; font-size: 10.5px; color: rgba(255,255,255,0.6); }

.share-channels {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  width: 100%;
  margin-bottom: 14px;
}
.share-channel-btn {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  border: none;
  border-radius: var(--radius-sm);
  padding: 12px 4px;
  font-size: 11px;
  font-weight: 700;
  background: var(--bg);
  color: var(--text-primary);
  box-shadow: var(--card-shadow-sm);
}
.share-channel-icon { font-size: 18px; }
.share-channel-btn.wa { background: #e9f9ee; }
html[data-theme='dark'] .share-channel-btn.wa { background: #123321; }
.share-channel-btn.fb { background: #eaf1fd; }
html[data-theme='dark'] .share-channel-btn.fb { background: #12213b; }
.share-channel-btn.xx { background: var(--bg); }
.share-channel-btn.cp { background: var(--bg); }
.share-channel-btn:active { transform: scale(0.95); }

/* ---------------------------------------------------------------------
   Settings
   --------------------------------------------------------------------- */
.settings-list { display: flex; flex-direction: column; gap: 18px; }
.settings-group {
  background: var(--bg-elevated);
  border-radius: var(--radius-md);
  box-shadow: var(--card-shadow-sm);
  padding: 16px;
}
.settings-group-title { font-size: 13px; color: var(--text-secondary); margin-bottom: 8px; text-transform: uppercase; letter-spacing: 0.6px; }
.setting-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 0;
  border-top: 1px solid var(--border-soft);
  font-size: 14.5px;
  font-weight: 600;
}
.setting-row:first-of-type { border-top: none; }
.select-input {
  border: 1.5px solid var(--border-soft);
  border-radius: 10px;
  padding: 8px 10px;
  background: var(--bg);
  color: var(--text-primary);
  font-size: 13.5px;
  font-weight: 600;
}
.settings-note { font-size: 11.5px; color: var(--text-secondary); margin-top: 6px; }

.toggle {
  width: 46px;
  height: 27px;
  border-radius: 999px;
  background: var(--border-soft);
  border: none;
  position: relative;
  transition: background var(--transition-fast);
}
.toggle[aria-checked='true'] { background: var(--accent); }
.toggle-knob {
  position: absolute;
  top: 3px;
  left: 3px;
  width: 21px;
  height: 21px;
  border-radius: 50%;
  background: white;
  box-shadow: 0 2px 4px rgba(0,0,0,0.25);
  transition: transform var(--transition-fast);
}
.toggle[aria-checked='true'] .toggle-knob { transform: translateX(19px); }

/* ---------------------------------------------------------------------
   How To Play
   --------------------------------------------------------------------- */
.howto-list { display: flex; flex-direction: column; gap: 14px; margin-bottom: 20px; }
.howto-step {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  background: var(--bg-elevated);
  border-radius: var(--radius-md);
  box-shadow: var(--card-shadow-sm);
  padding: 14px 16px;
}
.howto-num {
  flex: none;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: var(--accent);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 14px;
}
.howto-step p { font-size: 14.5px; line-height: 1.5; color: var(--text-primary); }

/* ---------------------------------------------------------------------
   Leaderboard
   --------------------------------------------------------------------- */
.leaderboard-note {
  font-size: 12px;
  color: var(--text-secondary);
  background: var(--bg-elevated);
  border-radius: var(--radius-sm);
  padding: 10px 14px;
  box-shadow: var(--card-shadow-sm);
  margin-bottom: 12px;
}
.my-best-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: linear-gradient(135deg, var(--purple-700), var(--purple-600));
  color: white;
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  font-weight: 800;
  font-size: 14px;
  margin-bottom: 14px;
}
.tabs {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
  margin-bottom: 16px;
  background: var(--bg-elevated);
  border-radius: 999px;
  padding: 5px;
  box-shadow: var(--card-shadow-sm);
}
.tab {
  border: none;
  background: transparent;
  padding: 9px 4px;
  border-radius: 999px;
  font-size: 11.5px;
  font-weight: 800;
  color: var(--text-secondary);
}
.tab.active { background: var(--accent); color: white; }
.leaderboard-list { display: flex; flex-direction: column; gap: 8px; }
.lb-row {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg-elevated);
  border-radius: var(--radius-sm);
  box-shadow: var(--card-shadow-sm);
  padding: 10px 14px;
}
.lb-row.is-player { border: 1.5px solid var(--gold-500); }
.lb-rank { font-weight: 800; width: 26px; color: var(--text-secondary); }
.lb-rank.top1 { color: var(--gold-500); }
.lb-rank.top2 { color: #a3a3a3; }
.lb-rank.top3 { color: #b06a35; }
.lb-name { flex: 1; font-weight: 700; font-size: 14px; }
.lb-score { font-weight: 800; color: var(--accent-strong); font-size: 14px; }
.lb-time { font-size: 12px; color: var(--text-secondary); width: 54px; text-align: right; }

/* ---------------------------------------------------------------------
   Toast
   --------------------------------------------------------------------- */
.toast {
  position: fixed;
  left: 50%;
  bottom: 26px;
  transform: translateX(-50%);
  background: var(--purple-900);
  color: white;
  padding: 12px 20px;
  border-radius: 999px;
  font-size: 13.5px;
  font-weight: 600;
  box-shadow: 0 8px 24px rgba(0,0,0,0.3);
  z-index: 200;
  max-width: 90%;
  text-align: center;
  transition: opacity var(--transition-med), transform var(--transition-med);
}
.toast.hidden { opacity: 0; pointer-events: none; transform: translate(-50%, 8px); }

/* ---------------------------------------------------------------------
   Relax mode
   --------------------------------------------------------------------- */
body.relax-mode .hud-time { opacity: 0.55; }
body.relax-mode .cell { font-size: clamp(17px, 5.2vw, 26px); }

/* ---------------------------------------------------------------------
   Responsive: tablet & desktop
   --------------------------------------------------------------------- */
@media (min-width: 640px) {
  .screen { padding: 24px 28px 32px; }
  .sudoku-board { width: min(100%, 560px); }
  .number-pad { grid-template-columns: repeat(9, 1fr); }
  .overlay-card { padding: 36px 32px; }
}

@media (min-width: 900px) {
  .screen:not(.screen-welcome):not(#screen-game) { max-width: 640px; }
  #screen-game { max-width: 680px; }
  .sudoku-board { width: min(100%, 600px); }
  .difficulty-grid { grid-template-columns: repeat(3, 1fr); }
}

/* Prevent accidental scrolling while actively playing */
#screen-game.active {
  overflow: hidden;
}