:root {
  --g24-navy: #2d248f;
  --g24-gold: #f1c96b;
  --g24-soft: #f7f3ff;
  --g24-line: rgba(45,36,143,0.13);
  --g24-muted: #6e6894;
}

.game24-bg {
  position: fixed;
  inset: 0;
  z-index: -3;
  background:
    radial-gradient(circle at 12% 10%, rgba(241,201,107,0.22), transparent 26%),
    radial-gradient(circle at 88% 22%, rgba(84,66,213,0.16), transparent 30%),
    linear-gradient(180deg, #fcfbff, #f7f3ff 55%, #fffdf7);
}

.game24-main {
  padding: 34px 0 54px;
}

.game24-shell {
  display: grid;
  gap: 18px;
}

.game24-header {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: stretch;
  background: rgba(255,255,255,0.92);
  border: 1px solid var(--g24-line);
  border-radius: 30px;
  box-shadow: 0 18px 48px rgba(45,36,143,0.12);
  padding: clamp(22px, 4vw, 34px);
}

.game24-header h1 {
  margin: 12px 0 8px;
  color: var(--g24-navy);
  font-size: clamp(2.2rem, 5vw, 4rem);
  line-height: 1;
}

.game24-header p {
  margin: 0;
  color: var(--g24-muted);
  line-height: 1.8;
  max-width: 720px;
}

.game24-score {
  min-width: 112px;
  border-radius: 24px;
  background: linear-gradient(135deg, rgba(45,36,143,0.1), rgba(241,201,107,0.24));
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  color: var(--g24-navy);
}

.game24-score span {
  font-weight: 800;
  color: var(--g24-muted);
}

.game24-score strong {
  font-size: 2.8rem;
  line-height: 1;
}

.level-panel {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.level-btn {
  text-align: left;
  border: 1px solid var(--g24-line);
  border-radius: 22px;
  padding: 18px;
  font-family: inherit;
  background: rgba(255,255,255,0.9);
  box-shadow: 0 12px 32px rgba(45,36,143,0.08);
  cursor: pointer;
  transition: transform 0.18s ease, border 0.18s ease, background 0.18s ease;
}

.level-btn:hover {
  transform: translateY(-3px);
}

.level-btn.active {
  border-color: rgba(45,36,143,0.55);
  background: linear-gradient(135deg, rgba(45,36,143,0.12), rgba(241,201,107,0.22));
}

.level-btn strong {
  display: block;
  color: var(--g24-navy);
  font-size: 1.12rem;
  margin-bottom: 6px;
}

.level-btn span {
  color: var(--g24-muted);
  line-height: 1.65;
}

.play-card,
.howto-card {
  background: rgba(255,255,255,0.94);
  border: 1px solid var(--g24-line);
  border-radius: 30px;
  box-shadow: 0 18px 48px rgba(45,36,143,0.12);
  padding: clamp(18px, 3vw, 28px);
}

.puzzle-top,
.expression-title {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  align-items: center;
}

.puzzle-top h2,
.operator-wrap h2,
.expression-title h2,
.howto-card h2 {
  color: var(--g24-navy);
  margin: 0 0 6px;
}

.puzzle-top p {
  margin: 0;
  color: var(--g24-muted);
}

.small-btn {
  border: 0;
  background: var(--g24-navy);
  color: white;
  font-family: inherit;
  font-weight: 800;
  border-radius: 14px;
  padding: 11px 14px;
  cursor: pointer;
  white-space: nowrap;
}

.small-btn.ghost {
  background: var(--g24-soft);
  color: var(--g24-navy);
  border: 1px solid var(--g24-line);
}

.number-row,
.operator-row,
.paren-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 14px;
}

.operator-wrap {
  margin-top: 24px;
}

.token-btn {
  border: 1px solid var(--g24-line);
  font-family: inherit;
  font-weight: 900;
  border-radius: 18px;
  cursor: pointer;
  transition: transform 0.12s ease, opacity 0.12s ease, background 0.12s ease;
}

.token-btn:hover {
  transform: translateY(-2px);
}

.num-token {
  width: 76px;
  height: 76px;
  font-size: 2.1rem;
  color: var(--g24-navy);
  background: #fffdf7;
  box-shadow: 0 12px 26px rgba(45,36,143,0.1);
}

.op-token {
  min-width: 58px;
  height: 58px;
  padding: 0 18px;
  font-size: 1.8rem;
  color: var(--g24-navy);
  background: var(--g24-soft);
}

.token-btn.used {
  opacity: 0.32;
  pointer-events: none;
}

.hidden {
  display: none !important;
}

.expression-wrap {
  margin-top: 24px;
}

.expression-strip {
  min-height: 82px;
  display: flex;
  align-items: center;
  gap: 10px;
  overflow-x: auto;
  border-radius: 22px;
  padding: 14px;
  background: linear-gradient(135deg, rgba(45,36,143,0.06), rgba(241,201,107,0.12));
  border: 1px solid var(--g24-line);
}

.expr-token {
  flex: 0 0 auto;
  min-width: 54px;
  height: 54px;
  padding: 0 14px;
  border: 1px solid var(--g24-line);
  border-radius: 16px;
  background: white;
  color: var(--g24-navy);
  font-family: inherit;
  font-size: 1.45rem;
  font-weight: 900;
  cursor: pointer;
  box-shadow: 0 8px 18px rgba(45,36,143,0.08);
}

.empty-expression {
  color: var(--g24-muted);
  font-weight: 700;
}

.result-panel {
  margin-top: 18px;
  border-radius: 22px;
  padding: 16px 18px;
  background: #fbfaff;
  border: 1px solid var(--g24-line);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
}

.result-label {
  display: block;
  color: var(--g24-muted);
  font-weight: 800;
  font-size: 0.9rem;
}

#liveResult {
  color: var(--g24-navy);
  font-size: 1.45rem;
}

.result-note {
  color: var(--g24-muted);
  text-align: right;
}

.action-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 18px;
}

.feedback-box {
  margin-top: 16px;
  padding: 16px 18px;
  border-radius: 18px;
  background: var(--g24-soft);
  color: var(--g24-navy);
  font-weight: 800;
  line-height: 1.75;
}

.feedback-box.correct {
  background: rgba(75, 201, 140, 0.14);
  color: #16623e;
}

.feedback-box.wrong {
  background: rgba(255, 120, 120, 0.14);
  color: #8d2727;
}

.feedback-box.info {
  background: rgba(241,201,107,0.22);
  color: #6c4a00;
}

.howto-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.howto-grid div {
  border-radius: 20px;
  padding: 16px;
  background: #fbfaff;
  border: 1px solid var(--g24-line);
}

.howto-grid strong {
  color: var(--g24-navy);
}

.howto-grid p {
  color: var(--g24-muted);
  margin: 8px 0 0;
  line-height: 1.7;
}

@media (max-width: 880px) {
  .level-panel,
  .howto-grid {
    grid-template-columns: 1fr;
  }

  .game24-header {
    flex-direction: column;
  }

  .game24-score {
    min-height: 92px;
    width: 100%;
  }
}

@media (max-width: 560px) {
  .game24-main {
    padding-top: 20px;
  }

  .game24-header,
  .play-card,
  .howto-card {
    border-radius: 24px;
  }

  .puzzle-top,
  .expression-title,
  .result-panel {
    align-items: stretch;
    flex-direction: column;
  }

  .result-note {
    text-align: left;
  }

  .num-token {
    width: 64px;
    height: 64px;
    font-size: 1.85rem;
    border-radius: 16px;
  }

  .op-token {
    min-width: 52px;
    height: 52px;
    font-size: 1.55rem;
  }

  .expression-strip {
    min-height: 72px;
  }

  .expr-token {
    min-width: 48px;
    height: 48px;
    font-size: 1.28rem;
  }

  .action-row .btn {
    width: 100%;
  }
}