:root {
  color-scheme: light;
  --ink: #16231f;
  --muted: #58706a;
  --paper: #fffef8;
  --panel: #ffffff;
  --line: #d7e6df;
  --mint: #2f7d6b;
  --mint-soft: #dff5ef;
  --sun: #ffd166;
  --sky: #83c5ff;
  --coral: #ff8a7a;
  --shadow: 0 18px 45px rgba(22, 35, 31, 0.13);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    linear-gradient(180deg, #e9f7ff 0%, #fff9e8 48%, #eefaf3 100%);
  color: var(--ink);
  font-family: "Arial Rounded MT Bold", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  letter-spacing: 0;
}

[hidden] {
  display: none !important;
}

button {
  font: inherit;
}

.lobby-screen {
  width: min(980px, 100%);
  min-height: 100vh;
  margin: 0 auto;
  padding: max(24px, env(safe-area-inset-top)) max(16px, env(safe-area-inset-right)) max(24px, env(safe-area-inset-bottom)) max(16px, env(safe-area-inset-left));
  display: grid;
  align-content: center;
  gap: 28px;
}

.lobby-title {
  text-align: center;
}

.lobby-title h1 {
  writing-mode: horizontal-tb;
  font-size: clamp(2.6rem, 8vw, 5.8rem);
}

.game-menu {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.game-card {
  min-height: 230px;
  border: 3px solid #17352e;
  border-radius: 8px;
  padding: 22px;
  background: #fff;
  color: var(--ink);
  box-shadow: var(--shadow);
  display: grid;
  align-content: center;
  justify-items: start;
  gap: 12px;
  text-align: left;
}

.game-card:disabled {
  opacity: 0.55;
}

.math-card {
  background: linear-gradient(150deg, #fff7db, #e3f8ff);
}

.english-card {
  background: linear-gradient(150deg, #eef2ff, #e4fff3);
}

.chinese-card {
  background: linear-gradient(150deg, #fff1f1, #fff8df);
}

.game-icon {
  min-width: 78px;
  min-height: 58px;
  border-radius: 8px;
  padding: 10px 12px;
  background: var(--mint);
  color: #fff;
  display: grid;
  place-items: center;
  font-size: 1.45rem;
  font-weight: 900;
}

.game-name {
  font-size: 2rem;
  font-weight: 900;
}

.mode-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  margin-top: 8px;
}

.mode-card {
  min-height: 220px;
  border: 3px solid #17352e;
  border-radius: 8px;
  padding: 22px;
  background: linear-gradient(150deg, #fff7db, #e3f8ff);
  color: var(--ink);
  display: grid;
  align-content: center;
  gap: 12px;
  text-align: left;
}

.mode-title {
  font-size: 2rem;
  font-weight: 900;
}

.mode-desc {
  color: var(--muted);
  font-weight: 800;
}

.game-desc {
  color: var(--muted);
  font-size: 1rem;
  font-weight: 800;
}

.shell {
  width: min(1120px, 100%);
  margin: 0 auto;
  min-height: 100vh;
  padding: max(18px, env(safe-area-inset-top)) max(16px, env(safe-area-inset-right)) max(22px, env(safe-area-inset-bottom)) max(16px, env(safe-area-inset-left));
  display: grid;
  grid-template-columns: 176px minmax(320px, 1fr);
  gap: 18px;
  align-items: stretch;
}

.hero {
  min-height: 680px;
  border-radius: 8px;
  padding: 18px;
  background: linear-gradient(160deg, #fff7db, #e3f8ff 62%, #dff5ef);
  box-shadow: var(--shadow);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.hero-art {
  min-height: 230px;
  display: grid;
  place-items: center;
}

.hero-art img {
  width: min(100%, 150px);
  filter: drop-shadow(0 18px 22px rgba(47, 125, 107, 0.18));
}

.hero-copy {
  display: grid;
  justify-items: center;
  gap: 12px;
}

.eyebrow,
.label {
  margin: 0 0 6px;
  color: var(--mint);
  font-size: 0.84rem;
  font-weight: 800;
}

h1,
h2,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 6px;
  font-size: clamp(2.4rem, 4vw, 4.2rem);
  line-height: 1.08;
  writing-mode: vertical-rl;
  text-orientation: mixed;
}

h2 {
  margin-bottom: 4px;
  font-size: 1.45rem;
}

.muted {
  margin-bottom: 0;
  color: var(--muted);
}

.game-board {
  min-height: 680px;
  border-radius: 8px;
  padding: 22px;
  background: rgba(255, 255, 255, 0.88);
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.topbar,
.stats,
.actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.back-button {
  min-height: 36px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--muted);
  padding: 0 10px;
  margin-bottom: 10px;
  font-size: 0.9rem;
  font-weight: 800;
}

.timer {
  min-width: 86px;
  min-height: 54px;
  border-radius: 8px;
  background: var(--mint-soft);
  color: var(--mint);
  display: grid;
  place-items: center;
  font-size: 1.25rem;
  font-weight: 900;
}

.level-track {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
}

.level-dot {
  min-height: 44px;
  border: 2px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--muted);
  font-weight: 900;
}

.level-dot[data-active="true"] {
  border-color: var(--mint);
  background: var(--mint);
  color: #fff;
}

.level-dot:disabled {
  opacity: 0.45;
}

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

.stats > div {
  min-height: 72px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  display: grid;
  place-items: center;
  padding: 8px;
}

.stat-value {
  font-size: 1.55rem;
  font-weight: 900;
}

.stat-label {
  color: var(--muted);
  font-size: 0.82rem;
}

.progress-shell {
  height: 16px;
  border-radius: 999px;
  background: #e8efe9;
  overflow: hidden;
}

.progress-fill {
  width: 0%;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--sky), var(--mint), var(--sun));
  transition: width 220ms ease;
}

.problem-card {
  min-height: 150px;
  border: 3px solid #17352e;
  border-radius: 8px;
  background: #fff;
  display: grid;
  grid-template-columns: 1fr auto 120px;
  align-items: center;
  gap: 18px;
  padding: 20px;
}

.problem-card[data-layout="vertical"] {
  grid-template-columns: 1fr 120px;
  min-height: 250px;
}

.problem-card[data-layout="vertical"] .problem {
  text-align: right;
}

.problem-card[data-layout="vertical"] .equals {
  display: none;
}

.problem,
.answer,
.equals {
  font-size: clamp(2.8rem, 10vw, 5.8rem);
  line-height: 1;
  font-weight: 900;
  text-align: center;
}

.answer {
  color: var(--coral);
}

.vertical-problem {
  width: min(280px, 100%);
  margin-left: auto;
  display: grid;
  gap: 8px;
  font-variant-numeric: tabular-nums;
}

.place-labels {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
  padding-right: 4px;
  color: var(--muted);
  font-size: 1rem;
  font-weight: 800;
}

.vertical-number {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
  align-items: center;
  font-size: clamp(3.2rem, 8vw, 5.6rem);
  line-height: 1;
}

.vertical-second {
  position: relative;
}

.vertical-second b {
  position: absolute;
  left: -46px;
  color: var(--mint);
  font-size: 0.72em;
}

.vertical-line {
  height: 5px;
  border-radius: 999px;
  background: #17352e;
}

.feedback {
  min-height: 34px;
  margin: 0;
  font-size: 1.15rem;
  font-weight: 800;
  text-align: center;
}

.feedback[data-tone="good"] {
  color: var(--mint);
}

.feedback[data-tone="try"] {
  color: #b75044;
}

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

.key {
  min-height: 68px;
  border: 0;
  border-radius: 8px;
  background: #f2f7f4;
  color: var(--ink);
  font-size: 1.6rem;
  font-weight: 900;
  box-shadow: inset 0 -4px 0 rgba(22, 35, 31, 0.08);
}

.key:active,
.action:active,
.level-dot:active {
  transform: translateY(1px);
}

.key-enter {
  grid-column: 1 / -1;
  background: var(--mint);
  color: white;
}

.actions {
  flex-wrap: wrap;
}

.action {
  min-height: 48px;
  border: 2px solid var(--mint);
  border-radius: 8px;
  background: #fff;
  color: var(--mint);
  padding: 0 16px;
  font-weight: 900;
}

.action.primary {
  background: var(--mint);
  color: #fff;
}

.action.quiet {
  border-color: var(--line);
  color: var(--muted);
}

.action:disabled {
  opacity: 0.45;
}

.summary {
  border-radius: 8px;
  background: var(--mint-soft);
  padding: 12px 14px;
  color: var(--mint);
  font-weight: 800;
}

.summary p {
  margin: 0;
}

.english-art {
  min-height: 250px;
}

.abc-stack {
  display: grid;
  gap: 10px;
}

.abc-stack span {
  width: 108px;
  height: 82px;
  border: 4px solid #17352e;
  border-radius: 8px;
  background: #fff;
  display: grid;
  place-items: center;
  font-size: 3rem;
  font-weight: 900;
  color: var(--mint);
  box-shadow: 0 10px 0 rgba(22, 35, 31, 0.08);
}

.word-card {
  min-height: 190px;
  border: 3px solid #17352e;
  border-radius: 8px;
  background: #fff;
  padding: 22px;
  display: grid;
  justify-items: center;
  align-content: center;
  gap: 12px;
}

.word-label {
  margin: 0;
  color: var(--muted);
  font-weight: 800;
}

.word {
  font-size: clamp(3rem, 9vw, 6.2rem);
  line-height: 1;
  font-weight: 900;
  color: var(--mint);
  text-align: center;
  overflow-wrap: anywhere;
}

.speak-button {
  min-height: 46px;
  border: 2px solid var(--mint);
  border-radius: 8px;
  background: var(--mint-soft);
  color: var(--mint);
  padding: 0 18px;
  font-weight: 900;
}

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

.choice-grid[data-count="2"] {
  grid-template-columns: repeat(2, 1fr);
}

.choice-button {
  min-height: 82px;
  border: 0;
  border-radius: 8px;
  background: #f2f7f4;
  color: var(--ink);
  font-size: 1.45rem;
  font-weight: 900;
  box-shadow: inset 0 -4px 0 rgba(22, 35, 31, 0.08);
}

.sudoku-layout {
  display: grid;
  grid-template-columns: minmax(320px, 1fr) minmax(220px, 0.55fr);
  gap: 16px;
  align-items: start;
}

.sudoku-grid {
  aspect-ratio: 1;
  width: min(100%, 560px);
  margin: 0 auto;
  display: grid;
  border: 4px solid #17352e;
  border-radius: 8px;
  overflow: hidden;
  background: #17352e;
  gap: 2px;
}

.sudoku-cell {
  min-width: 0;
  min-height: 0;
  border: 0;
  background: #fff;
  color: var(--ink);
  font-size: clamp(1.25rem, 5vw, 3.4rem);
  font-weight: 900;
  font-variant-numeric: tabular-nums;
  position: relative;
}

.sudoku-grid[data-size="9"] .sudoku-cell {
  font-size: clamp(1rem, 3.6vw, 2.4rem);
}

.sudoku-cell[data-box-right="true"] {
  box-shadow: inset -3px 0 0 #17352e;
}

.sudoku-cell[data-box-bottom="true"] {
  box-shadow: inset 0 -3px 0 #17352e;
}

.sudoku-cell[data-box-right="true"][data-box-bottom="true"] {
  box-shadow: inset -3px 0 0 #17352e, inset 0 -3px 0 #17352e;
}

.sudoku-cell[data-given="true"] {
  background: var(--mint-soft);
  color: var(--mint);
}

.sudoku-cell[data-selected="true"] {
  outline: 4px solid var(--sun);
  outline-offset: -6px;
}

.sudoku-cell[data-conflict="true"] {
  background: #ffe3df;
  color: #b75044;
}

.sudoku-notes {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  color: #7a6650;
  font-size: clamp(0.78rem, 2.5vw, 1.35rem);
  font-weight: 900;
  letter-spacing: 0;
  pointer-events: none;
}

.sudoku-side {
  display: grid;
  gap: 14px;
}

.sudoku-timers {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}

.sudoku-timers > div,
.sudoku-countdown-control {
  border: 2px solid var(--line);
  border-radius: 8px;
  background: #fff;
  padding: 12px;
}

.timer-label {
  display: block;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 900;
}

.sudoku-timers strong {
  display: block;
  margin-top: 4px;
  color: var(--ink);
  font-size: 1.55rem;
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.sudoku-countdown-control {
  display: grid;
  gap: 10px;
}

.sudoku-countdown-control label {
  color: var(--ink);
  font-weight: 900;
}

.sudoku-countdown-control input[type="range"] {
  width: 100%;
  accent-color: var(--mint);
}

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

.sudoku-size-switch {
  grid-template-columns: repeat(2, 1fr);
}

.difficulty-button {
  min-height: 46px;
  border: 2px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--muted);
  font-weight: 900;
}

.difficulty-button[data-active="true"] {
  border-color: var(--mint);
  background: var(--mint);
  color: #fff;
}

.sudoku-note-toggle {
  width: 100%;
  min-height: 52px;
}

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

.sudoku-pad[data-size="9"] {
  grid-template-columns: repeat(3, 1fr);
}

.sudoku-key {
  min-height: 66px;
  border: 0;
  border-radius: 8px;
  background: #f2f7f4;
  color: var(--ink);
  font-size: 1.45rem;
  font-weight: 900;
  box-shadow: inset 0 -4px 0 rgba(22, 35, 31, 0.08);
}

.sudoku-clear {
  grid-column: 1 / -1;
  color: var(--muted);
}

@media (max-width: 820px) {
  .game-menu {
    grid-template-columns: 1fr;
  }

  .game-card {
    min-height: 150px;
  }

  .mode-grid,
  .sudoku-layout {
    grid-template-columns: 1fr;
  }

  .shell {
    grid-template-columns: 1fr;
  }

  .hero,
  .game-board {
    min-height: auto;
  }

  .hero {
    padding: 18px;
    display: grid;
    grid-template-columns: 104px 1fr;
    align-items: center;
  }

  .hero-art {
    min-height: 104px;
  }

  .hero-art img {
    width: 104px;
  }

  .abc-stack {
    display: flex;
  }

  .abc-stack span {
    width: 58px;
    height: 58px;
    font-size: 2rem;
  }

  h1 {
    font-size: 2.6rem;
    writing-mode: horizontal-tb;
  }

  .problem-card {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .problem-card[data-layout="vertical"] {
    grid-template-columns: 1fr;
  }

  .problem-card[data-layout="vertical"] .problem {
    text-align: center;
  }

  .vertical-problem {
    margin: 0 auto;
  }

  .problem,
  .answer,
  .equals {
    font-size: 3.6rem;
  }
}

@media (max-width: 520px) {
  .topbar {
    align-items: stretch;
    flex-direction: column;
  }

  .timer {
    width: 100%;
  }

  .stats {
    gap: 8px;
  }

  .stat-value {
    font-size: 1.2rem;
  }

  .key {
    min-height: 62px;
  }

  .action {
    flex: 1 1 45%;
    padding: 0 10px;
  }

  .choice-grid {
    grid-template-columns: 1fr;
  }
}