html, body { margin: 0; padding: 0; min-height: 100%; background: #f4ede0; }
body { font-family: "Inter", system-ui, sans-serif; color: #191612; }
* { box-sizing: border-box; }
button { font-family: inherit; }
#root { min-height: 100vh; display: flex; flex-direction: column; }
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
}
.skip-link:focus {
  left: 1rem;
  top: 1rem;
  z-index: 100;
  padding: 0.65rem 0.85rem;
  background: #fff;
  color: #0c0d0f;
  border: 2px solid currentColor;
}
.site-header { display: block; }
.topbar {
  padding-top: env(safe-area-inset-top, 0px);
  background: #0c0d0f;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.topbar-content {
  max-width: 1100px; margin: 0 auto;
  padding: 0.55rem 1.1rem; gap: 1rem;
  display: flex; align-items: center; justify-content: space-between;
}
.topbar .brand, .topbar .brand a {
  color: #f0f1f4; text-decoration: none;
}
.style-bar {
  position: sticky; top: 0; z-index: 40;
  display: flex; justify-content: center; align-items: center; gap: 14px;
  padding: 10px 20px; background: rgba(255,255,255,0.7);
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(0,0,0,0.08);
  font-family: ui-sans-serif, system-ui;
}
.style-bar.dark {
  background: rgba(19,20,26,0.7);
  border-bottom: 1px solid rgba(240,235,220,0.12);
  color: #f0ebdc;
}
.style-bar .label {
  font-size: 10px; letter-spacing: 0.18em; text-transform: uppercase; opacity: 0.55;
}
.sudoku-history-trigger {
  display: inline-flex; align-items: center; gap: 7px;
  min-height: 34px; padding: 6px 11px;
  border: 1px solid rgba(25,22,18,0.24); border-radius: 2px;
  background: rgba(255,255,255,0.26); color: inherit;
  font-size: 11px; font-weight: 650; letter-spacing: 0.08em;
  text-transform: uppercase; cursor: pointer;
}
.style-bar.dark .sudoku-history-trigger { border-color: rgba(240,235,220,0.24); background: rgba(255,255,255,0.04); }
.sudoku-history-trigger:hover { background: rgba(255,255,255,0.58); }
.style-bar.dark .sudoku-history-trigger:hover { background: rgba(255,255,255,0.1); }
.sudoku-history-trigger:focus-visible { outline: 2px solid currentColor; outline-offset: 3px; }
.sudoku-history-trigger-grid { font-size: 17px; line-height: 1; }

body.sudoku-history-open { overflow: hidden; }
body.sudoku-shared-choice-open { overflow: hidden; }
.sudoku-shared-overlay {
  --shared-bg: #f6f0e5;
  --shared-ink: #1d1914;
  --shared-muted: #756c61;
  --shared-rule: rgba(38,31,23,0.2);
  --shared-soft: rgba(76,60,42,0.07);
  --shared-accent: #6e3f24;
  position: fixed; inset: 0; z-index: 130;
  display: grid; place-items: center;
  padding: max(20px, env(safe-area-inset-top)) 20px max(20px, env(safe-area-inset-bottom));
  background: rgba(12,13,15,0.62);
  backdrop-filter: blur(5px); -webkit-backdrop-filter: blur(5px);
  animation: sudoku-history-fade 180ms ease-out both;
}
.sudoku-shared-overlay.theme-classic {
  --shared-bg: #f3f3ef; --shared-ink: #171817; --shared-muted: #696b67;
  --shared-rule: rgba(25,26,24,0.19); --shared-soft: rgba(25,26,24,0.055); --shared-accent: #284d66;
}
.sudoku-shared-overlay.theme-nocturne {
  --shared-bg: #16171d; --shared-ink: #f1ecdf; --shared-muted: #a6a093;
  --shared-rule: rgba(240,235,220,0.18); --shared-soft: rgba(255,255,255,0.055); --shared-accent: #d39a58;
}
.sudoku-shared-panel {
  width: min(540px, 100%); padding: clamp(26px, 5vw, 42px);
  border: 1px solid var(--shared-rule); border-radius: 3px;
  background: var(--shared-bg); color: var(--shared-ink);
  box-shadow: 0 26px 90px rgba(0,0,0,0.34);
  animation: sudoku-shared-enter 220ms cubic-bezier(.2,.75,.2,1) both;
}
@keyframes sudoku-shared-enter { from { transform: translateY(14px) scale(.985); opacity: 0.72; } to { transform: translateY(0) scale(1); opacity: 1; } }
.sudoku-shared-kicker {
  display: block; margin-bottom: 12px; color: var(--shared-accent);
  font-size: 10px; font-weight: 750; letter-spacing: 0.18em; text-transform: uppercase;
}
.sudoku-shared-panel h2 {
  margin: 0; font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(30px, 6vw, 44px); font-weight: 500; line-height: 1.05;
}
.sudoku-shared-panel p {
  margin: 18px 0 0; color: var(--shared-muted); font-size: 14px; line-height: 1.65;
}
.sudoku-shared-actions { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-top: 26px; }
.sudoku-shared-actions button {
  min-height: 46px; padding: 10px 14px; border: 1px solid var(--shared-rule);
  background: transparent; color: inherit; cursor: pointer;
  font-size: 11px; font-weight: 720; letter-spacing: 0.08em; text-transform: uppercase;
}
.sudoku-shared-actions button:hover { border-color: var(--shared-accent); }
.sudoku-shared-actions button:focus-visible { outline: 2px solid var(--shared-accent); outline-offset: 3px; }
.sudoku-shared-actions .sudoku-shared-primary { border-color: var(--shared-accent); background: var(--shared-accent); color: var(--shared-bg); }
.sudoku-shared-actions .sudoku-shared-secondary { background: var(--shared-soft); }
.sudoku-shared-panel small { display: block; margin-top: 15px; color: var(--shared-muted); font-size: 11px; line-height: 1.5; }
.sudoku-history-overlay {
  --history-bg: #f6f0e5;
  --history-ink: #1d1914;
  --history-muted: #756c61;
  --history-rule: rgba(38,31,23,0.18);
  --history-soft: rgba(76,60,42,0.06);
  --history-accent: #6e3f24;
  position: fixed; inset: 0; z-index: 120;
  display: flex; justify-content: flex-end;
  background: rgba(12,13,15,0.54);
  backdrop-filter: blur(3px); -webkit-backdrop-filter: blur(3px);
  animation: sudoku-history-fade 180ms ease-out both;
}
.sudoku-history-overlay.theme-classic {
  --history-bg: #f3f3ef; --history-ink: #171817; --history-muted: #696b67;
  --history-rule: rgba(25,26,24,0.17); --history-soft: rgba(25,26,24,0.045); --history-accent: #284d66;
}
.sudoku-history-overlay.theme-nocturne {
  --history-bg: #16171d; --history-ink: #f1ecdf; --history-muted: #a6a093;
  --history-rule: rgba(240,235,220,0.16); --history-soft: rgba(255,255,255,0.045); --history-accent: #d39a58;
}
@keyframes sudoku-history-fade { from { opacity: 0; } to { opacity: 1; } }
@keyframes sudoku-history-enter { from { transform: translateX(22px); opacity: 0.75; } to { transform: translateX(0); opacity: 1; } }
.sudoku-history-panel {
  width: min(620px, 94vw); height: 100%; overflow-y: auto;
  padding: max(28px, env(safe-area-inset-top)) 30px max(32px, env(safe-area-inset-bottom));
  background: var(--history-bg);
  color: var(--history-ink); box-shadow: -18px 0 70px rgba(0,0,0,0.24);
  animation: sudoku-history-enter 220ms cubic-bezier(.2,.75,.2,1) both;
}
.sudoku-history-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 24px; margin-bottom: 20px; }
.sudoku-history-head h2 { margin: 3px 0 0; font-family: Georgia, "Times New Roman", serif; font-size: clamp(30px, 5vw, 44px); font-weight: 500; line-height: 1; }
.sudoku-history-kicker { display: block; color: var(--history-accent); font-size: 10px; font-weight: 750; letter-spacing: 0.18em; text-transform: uppercase; }
.sudoku-history-close {
  width: 40px; height: 40px; flex: none; border: 1px solid var(--history-rule); border-radius: 50%;
  background: var(--history-soft); color: inherit; font-size: 27px; line-height: 1; cursor: pointer;
}
.sudoku-history-close:hover { border-color: var(--history-accent); color: var(--history-accent); }
.sudoku-history-tabs { display: grid; grid-template-columns: repeat(3,1fr); border: 1px solid var(--history-rule); background: var(--history-bg); }
.sudoku-history-tabs button {
  min-height: 42px; border: 0; border-right: 1px solid var(--history-rule); background: transparent; color: var(--history-muted);
  font-size: 11px; font-weight: 700; letter-spacing: 0.12em; text-transform: uppercase; cursor: pointer;
}
.sudoku-history-tabs button:last-child { border-right: 0; }
.sudoku-history-tabs button[aria-selected="true"] { background: var(--history-ink); color: var(--history-bg); }
.sudoku-history-view { padding: 22px 0; }
.sudoku-history-summary { display: grid; grid-template-columns: repeat(4,1fr); border: 1px solid var(--history-rule); background: var(--history-bg); }
.sudoku-history-summary.wide { grid-template-columns: repeat(3,1fr); }
.sudoku-history-metric { min-height: 90px; padding: 14px; border-right: 1px solid var(--history-rule); display: flex; flex-direction: column; justify-content: space-between; }
.sudoku-history-summary.wide .sudoku-history-metric:nth-child(3n) { border-right: 0; }
.sudoku-history-summary.wide .sudoku-history-metric:nth-child(n+4) { border-top: 1px solid var(--history-rule); }
.sudoku-history-metric:last-child { border-right: 0; }
.sudoku-history-metric > span, .sudoku-history-metric small { color: var(--history-muted); font-size: 10px; letter-spacing: 0.1em; text-transform: uppercase; }
.sudoku-history-metric strong { font-family: Georgia, "Times New Roman", serif; font-size: 23px; font-weight: 500; }
.sudoku-history-note, .sudoku-history-footnote { color: var(--history-muted); font-size: 12px; line-height: 1.55; }
.sudoku-history-note { margin: 14px 0 8px; padding-left: 11px; border-left: 2px solid var(--history-accent); }
.sudoku-history-footnote { margin: 18px 0 0; }
.sudoku-history-list { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--history-rule); }
.sudoku-history-list li { display: grid; grid-template-columns: 42px 1fr auto; align-items: center; gap: 13px; min-height: 76px; border-bottom: 1px solid var(--history-rule); }
.sudoku-attempt-stamp { width: 38px; height: 38px; padding: 4px; display: grid; grid-template-columns: repeat(3,1fr); gap: 2px; border: 1px solid var(--history-rule); background: var(--history-bg); }
.sudoku-attempt-stamp i { display: block; border: 1px solid var(--history-rule); }
.sudoku-attempt-stamp i.is-filled { background: var(--history-accent); border-color: var(--history-accent); }
.sudoku-attempt-stamp.is-abandoned i.is-filled { opacity: 0.48; }
.sudoku-attempt-stamp.is-in_progress { box-shadow: inset 0 0 0 2px var(--history-bg), inset 0 0 0 3px var(--history-accent); }
.sudoku-history-row-main, .sudoku-history-row-time { display: flex; flex-direction: column; gap: 4px; min-width: 0; }
.sudoku-history-row-main strong { font-family: Georgia, "Times New Roman", serif; font-size: 17px; font-weight: 500; }
.sudoku-history-row-main span, .sudoku-history-row-time span { color: var(--history-muted); font-size: 11px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; text-transform: capitalize; }
.sudoku-history-row-time { align-items: flex-end; text-align: right; }
.sudoku-history-row-time strong { font-variant-numeric: tabular-nums; font-size: 13px; }
.sudoku-history-more, .sudoku-history-primary {
  display: inline-flex; align-items: center; justify-content: center; min-height: 42px; margin-top: 18px; padding: 10px 16px;
  border: 1px solid var(--history-ink); border-radius: 1px; background: var(--history-ink); color: var(--history-bg);
  font-size: 11px; font-weight: 750; letter-spacing: 0.1em; text-decoration: none; text-transform: uppercase; cursor: pointer;
}
.sudoku-history-more { width: 100%; background: transparent; color: var(--history-ink); }
.sudoku-history-primary:disabled, .sudoku-history-more:disabled { opacity: 0.55; cursor: wait; }
.sudoku-history-empty { min-height: 65vh; padding: 70px 20px; display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; }
.sudoku-history-empty.compact { min-height: 180px; padding: 40px 20px; }
.sudoku-history-empty .sudoku-attempt-stamp { width: 58px; height: 58px; margin-bottom: 18px; }
.sudoku-history-empty h3, .sudoku-coach h3 { margin: 0 0 10px; font-family: Georgia, "Times New Roman", serif; font-size: 25px; font-weight: 500; }
.sudoku-history-empty p, .sudoku-coach p { max-width: 450px; margin: 0; color: var(--history-muted); font-size: 13px; line-height: 1.65; }
.sudoku-history-loading { padding: 50px 0; color: var(--history-muted); text-align: center; font-family: Georgia, "Times New Roman", serif; }
.sudoku-history-error { padding: 11px 13px; border-left: 3px solid #b64132; background: rgba(182,65,50,0.09); font-size: 12px; line-height: 1.45; }
.sudoku-history-subhead { margin: 26px 0 8px; color: var(--history-muted); font-size: 10px; letter-spacing: 0.16em; text-transform: uppercase; }
.sudoku-history-difficulties { border-top: 1px solid var(--history-rule); }
.sudoku-history-difficulties > div { display: grid; grid-template-columns: 1fr 1.4fr 1.4fr; gap: 10px; padding: 13px 0; border-bottom: 1px solid var(--history-rule); font-size: 12px; }
.sudoku-history-difficulties strong { text-transform: capitalize; }
.sudoku-history-difficulties span { color: var(--history-muted); }
.sudoku-coach-intro { min-height: 58vh; display: flex; flex-direction: column; align-items: flex-start; justify-content: center; }
.sudoku-coach-mark { width: 58px; height: 58px; margin-bottom: 22px; display: grid; place-items: center; border: 1px solid var(--history-accent); border-radius: 50%; color: var(--history-accent); font-size: 25px; }
.sudoku-coach-report { padding-top: 8px; }
.sudoku-coach-report > h3 { max-width: 480px; margin-top: 8px; font-size: 31px; }
.sudoku-coach-columns { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; margin: 25px 0; }
.sudoku-coach-columns section { padding: 16px; border: 1px solid var(--history-rule); background: var(--history-bg); }
.sudoku-coach-columns h4 { margin: 0 0 10px; color: var(--history-accent); font-size: 10px; letter-spacing: 0.14em; text-transform: uppercase; }
.sudoku-coach-columns ul, .sudoku-coach-report details ul { margin: 0; padding-left: 18px; }
.sudoku-coach-columns li, .sudoku-coach-report details li { margin-bottom: 8px; font-size: 12px; line-height: 1.5; }
.sudoku-coach-actions { list-style: none; margin: 0; padding: 0; counter-reset: coach-step; }
.sudoku-coach-actions li { counter-increment: coach-step; display: grid; grid-template-columns: 35px 1fr; gap: 10px; padding: 13px 0; border-top: 1px solid var(--history-rule); }
.sudoku-coach-actions li::before { content: counter(coach-step, decimal-leading-zero); color: var(--history-accent); font-size: 11px; }
.sudoku-coach-actions strong, .sudoku-coach-actions span { grid-column: 2; }
.sudoku-coach-actions strong { font-family: Georgia, "Times New Roman", serif; font-size: 17px; font-weight: 500; }
.sudoku-coach-actions span { color: var(--history-muted); font-size: 12px; line-height: 1.5; }
.sudoku-coach-report details { margin-top: 20px; color: var(--history-muted); font-size: 12px; }
.sudoku-coach-report summary { cursor: pointer; }
.sudoku-history-panel button:focus-visible, .sudoku-history-panel a:focus-visible { outline: 2px solid var(--history-accent); outline-offset: 3px; }

@keyframes fcc-sudoku-reject-flash {
  0%   { opacity: 1; transform: scale(1.06); }
  18%  { opacity: 1; transform: scale(1); }
  100% { opacity: 0; transform: scale(0.94); }
}
.fcc-sudoku-reject-flash {
  display: inline-block;
  pointer-events: none;
  animation: fcc-sudoku-reject-flash 0.75s ease-out forwards;
}

.fcc-visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0 0 0 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

/* Digit-completion chorus: the nine correct copies answer the final move in
   a short spatial ripple, then the completed tray chip seals the moment. */
@keyframes fcc-sudoku-digit-chorus {
  0%   { opacity: 0; transform: scale(0.68); }
  24%  { opacity: 1; transform: scale(1.03); }
  58%  { opacity: 0.92; transform: scale(0.94); }
  100% { opacity: 0; transform: scale(1.12); }
}
@keyframes fcc-sudoku-digit-seal {
  0%   { opacity: 0; transform: scale(0.72); }
  28%  { opacity: 1; transform: scale(1.08); }
  62%  { opacity: 0.85; transform: scale(0.98); }
  100% { opacity: 0; transform: scale(1.18); }
}
.fcc-cell--digit-complete { isolation: isolate; }
.fcc-cell--digit-complete > span:not(.fcc-digit-completion-cell) {
  position: relative;
  z-index: 4;
}
.fcc-digit-completion-cell {
  position: absolute;
  inset: 7%;
  z-index: 3;
  pointer-events: none;
  border: 2px solid var(--sudoku-completion-accent);
  background: rgba(var(--sudoku-completion-accent-rgb), 0.08);
  box-shadow: inset 0 0 0 1px rgba(var(--sudoku-completion-accent-rgb), 0.2);
  opacity: 0;
  transform: scale(0.68);
  animation: fcc-sudoku-digit-chorus 0.94s cubic-bezier(.2,.8,.3,1) both;
  animation-delay: calc(var(--completion-order) * 45ms);
}
.fcc-sudoku-theme-classic .fcc-digit-completion-cell {
  border-radius: 3px;
}
.fcc-sudoku-theme-ledger .fcc-digit-completion-cell {
  inset: 5%;
  border-width: 1px;
  border-radius: 0;
  outline: 1px solid rgba(var(--sudoku-completion-accent-rgb), 0.45);
  outline-offset: -5px;
  background: linear-gradient(135deg,
    rgba(var(--sudoku-completion-accent-rgb), 0.12),
    rgba(var(--sudoku-completion-accent-rgb), 0.025));
}
.fcc-sudoku-theme-nocturne .fcc-digit-completion-cell {
  inset: 10%;
  border-width: 1px;
  border-radius: 50%;
  background: radial-gradient(circle,
    rgba(var(--sudoku-completion-accent-rgb), 0.18),
    rgba(var(--sudoku-completion-accent-rgb), 0.025) 66%,
    transparent 68%);
  box-shadow:
    0 0 12px rgba(var(--sudoku-completion-accent-rgb), 0.55),
    0 0 28px rgba(var(--sudoku-completion-accent-rgb), 0.24),
    inset 0 0 8px rgba(var(--sudoku-completion-accent-rgb), 0.3);
}
.fcc-digit-completion-chip {
  position: absolute;
  inset: -4px;
  z-index: 3;
  pointer-events: none;
  border: 2px solid var(--sudoku-completion-accent);
  box-shadow: 0 0 0 1px var(--sudoku-completion-surface),
              0 0 0 3px rgba(var(--sudoku-completion-accent-rgb), 0.32);
  opacity: 0;
  animation: fcc-sudoku-digit-seal 1.08s 0.24s cubic-bezier(.2,.8,.3,1) both;
}
.fcc-sudoku-theme-ledger .fcc-digit-completion-chip {
  inset: -3px;
  border-width: 1px;
  outline: 1px solid rgba(var(--sudoku-completion-accent-rgb), 0.5);
  outline-offset: 3px;
}
.fcc-sudoku-theme-nocturne .fcc-digit-completion-chip {
  box-shadow: 0 0 10px rgba(var(--sudoku-completion-accent-rgb), 0.65),
              0 0 24px rgba(var(--sudoku-completion-accent-rgb), 0.28);
}
@media (prefers-reduced-motion: reduce) {
  .fcc-sudoku-reject-flash { animation-duration: 0.4s; transform: none; }
  .fcc-digit-completion-cell,
  .fcc-digit-completion-chip {
    animation: none;
    opacity: 1;
    transform: none;
  }
}
@media (forced-colors: active) {
  .fcc-digit-completion-cell,
  .fcc-digit-completion-chip {
    border-color: Highlight;
    background: transparent;
    box-shadow: none;
    outline-color: CanvasText;
  }
}

/* Quiet pointer to the previous version, served at /legacy-sudoku/.
   Static HTML outside the React root; inherits page color so it reads
   on light (classic/ledger) and dark (nocturne) styles alike. */
.legacy-note {
  max-width: 1200px;
  margin: 0 auto;
  padding: 18px 24px 30px;
  font-family: ui-sans-serif, system-ui, sans-serif;
  font-size: 12.5px;
  letter-spacing: 0.02em;
  text-align: center;
  opacity: 0.65;
}
.legacy-note a { color: inherit; text-decoration: underline; }

/* Loaded before the React bundle so responsive layout and hint styling are
   correct on first paint without injecting those rules at runtime. */
.fcc-layout { display: grid; grid-template-columns: 1fr 280px; gap: 32px; max-width: 1100px; margin: 0 auto; }
.fcc-layout--nocturne { grid-template-columns: 1fr 300px; gap: 36px; }
.fcc-stats-classic { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.fcc-bests { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.fcc-ledger-bests { display: flex; gap: 28px; }
.fcc-noc-bests { display: flex; gap: 22px; }
.fcc-board-wrap { width: min(100%, 560px); }
.fcc-digit-tray { display: grid; grid-template-columns: repeat(10, 1fr); gap: 4px; width: min(100%, 560px); }
.fcc-controls { display: flex; flex-wrap: wrap; gap: 8px; }
.fcc-cell[aria-selected="true"] { outline: 2px solid currentColor; outline-offset: -2px; }
.fcc-cell:focus-visible { outline: 2px dashed currentColor; outline-offset: -2px; z-index: 1; }

@keyframes fccHintPulse {
  0%, 100% { box-shadow: inset 0 0 0 1.5px currentColor; opacity: 1; }
  50% { box-shadow: inset 0 0 0 3px currentColor; opacity: 0.75; }
}
.fcc-hint-target {
  animation: fccHintPulse 1.4s ease-in-out infinite;
  position: relative;
}

@media (max-width: 840px) {
  .fcc-layout, .fcc-layout--nocturne { grid-template-columns: 1fr !important; gap: 24px !important; }
  .fcc-stats-classic { grid-template-columns: repeat(2, 1fr); }
  .fcc-bests { grid-template-columns: repeat(3, 1fr); gap: 10px; }
  .fcc-ledger-bests, .fcc-noc-bests { flex-wrap: wrap; gap: 14px; }
  .fcc-board-wrap { max-width: 520px; margin: 0 auto; width: 100%; }
  .fcc-digit-tray { max-width: 520px; margin: 0 auto; }
  .fcc-header-split { flex-direction: column; gap: 10px; align-items: flex-start !important; }
  .fcc-controls { justify-content: center; }
  .fcc-page { padding: 20px 16px !important; }
  .fcc-h1 { font-size: 28px !important; }
}

@media (max-width: 520px) {
  .fcc-stats-classic { grid-template-columns: repeat(2, 1fr); }
  .fcc-bests { grid-template-columns: 1fr 1fr 1fr; font-size: 11px; }
  .fcc-digit-tray { grid-template-columns: repeat(5, 1fr); }
  .fcc-digit-tray > button:last-child { grid-column: span 5; padding: 6px !important; }
  .style-bar { justify-content: flex-start; gap: 8px; padding-inline: 10px; overflow-x: auto; }
  .style-bar .label { display: none; }
  .sudoku-history-trigger { margin-left: auto; white-space: nowrap; }
  .sudoku-history-overlay { align-items: flex-end; }
  .sudoku-history-panel {
    width: 100vw; height: min(92dvh, 780px); padding: 22px 17px max(24px, env(safe-area-inset-bottom));
    border-radius: 14px 14px 0 0; animation-name: sudoku-history-enter-mobile;
  }
  .sudoku-history-summary, .sudoku-history-summary.wide { grid-template-columns: repeat(2,1fr); }
  .sudoku-history-summary .sudoku-history-metric { border-top: 1px solid var(--history-rule); }
  .sudoku-history-summary .sudoku-history-metric:nth-child(-n+2) { border-top: 0; }
  .sudoku-history-summary .sudoku-history-metric:nth-child(2n) { border-right: 0; }
  .sudoku-history-list li { grid-template-columns: 38px 1fr auto; gap: 9px; }
  .sudoku-attempt-stamp { width: 34px; height: 34px; }
  .sudoku-history-difficulties > div { grid-template-columns: 1fr 1.5fr; }
  .sudoku-history-difficulties > div span:last-child { grid-column: 2; }
  .sudoku-coach-columns { grid-template-columns: 1fr; gap: 10px; }
  .sudoku-shared-overlay { align-items: end; padding: 12px; }
  .sudoku-shared-panel { padding: 28px 22px; border-radius: 10px; }
  .sudoku-shared-actions { grid-template-columns: 1fr; }
}

@keyframes sudoku-history-enter-mobile { from { transform: translateY(28px); opacity: 0.75; } to { transform: translateY(0); opacity: 1; } }

@media (prefers-reduced-motion: reduce) {
  .fcc-hint-target { animation: none; box-shadow: inset 0 0 0 2px currentColor; }
  .sudoku-history-overlay, .sudoku-history-panel,
  .sudoku-shared-overlay, .sudoku-shared-panel { animation: none; }
}

@media (forced-colors: active) {
  .sudoku-history-panel, .sudoku-history-tabs button[aria-selected="true"],
  .sudoku-history-primary, .sudoku-shared-panel,
  .sudoku-shared-primary { forced-color-adjust: auto; }
}
.sudoku-private-loading {
  flex: 1;
  min-height: min(72vh, 720px);
  display: grid;
  place-content: center;
  justify-items: center;
  gap: 0.8rem;
  background: #f4ede0;
  color: #191612;
  font: 600 0.75rem/1.2 ui-monospace, SFMono-Regular, Menlo, monospace;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.sudoku-private-loading.is-dark {
  background: #13141a;
  color: #f0ebdc;
}
.sudoku-private-loading small {
  max-width: 30rem;
  opacity: 0.62;
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-align: center;
  text-transform: none;
}

@media (forced-colors: active) {
  .fcc-cell[aria-invalid="true"] {
    outline: 3px solid Mark;
    outline-offset: -3px;
  }
}