:root {
  --bg: #f4fbf5;
  --surface: #ffffff;
  --surface-2: #eef9ef;
  --text: #213128;
  --muted: #587064;
  --primary: #7bc67b;
  --primary-strong: #57ad57;
  --danger: #ef8d8d;
  --border: #d7ead7;
  --shadow: 0 12px 30px rgba(27, 60, 37, 0.08);
  --row-highlight: #fff3b6;
  --col-highlight: #dff6d2;
  --cell-highlight: #ffd889;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background:
    radial-gradient(circle at top left, #fff9d7 0, transparent 26%),
    radial-gradient(circle at top right, #d7f7dc 0, transparent 18%),
    linear-gradient(180deg, #effbf2 0%, var(--bg) 100%);
  color: var(--text);
}

button, input { font: inherit; }

.app-shell {
  width: min(1400px, 100%);
  margin: 0 auto;
  padding: 20px;
}

.topbar {
  display: flex;
  gap: 16px;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 18px;
  flex-wrap: wrap;
}

h1 {
  margin: 0 0 6px;
  font-size: clamp(28px, 4vw, 42px);
}

.subtitle {
  margin: 0;
  color: var(--muted);
  font-size: 16px;
}

.layout {
  display: grid;
  grid-template-columns: 1.05fr 1fr;
  gap: 18px;
}

.card {
  background: var(--surface);
  border: 2px solid var(--border);
  border-radius: 28px;
  box-shadow: var(--shadow);
  padding: 18px;
}

.mode-select {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.mode-btn,
.secondary-btn,
.confirm-btn,
.option-btn {
  border: none;
  border-radius: 18px;
  cursor: pointer;
  transition: transform 0.12s ease, box-shadow 0.12s ease, background 0.12s ease;
}

.mode-btn {
  padding: 14px 18px;
  background: #eaf6ea;
  color: var(--text);
  font-weight: 700;
}

.mode-btn.active {
  background: var(--primary);
}

.mode-btn:hover,
.secondary-btn:hover,
.confirm-btn:hover,
.option-btn:hover,
.table-answer:hover {
  transform: translateY(-1px);
}

.status-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.badge {
  padding: 10px 14px;
  background: var(--surface-2);
  border: 2px solid var(--border);
  border-radius: 999px;
  font-weight: 700;
}

.dino-stage {
  position: relative;
  min-height: 360px;
  border-radius: 24px;
  overflow: hidden;
  background:
    linear-gradient(180deg, #d7f6ff 0%, #ecfbff 52%, #dff7cf 52%, #d6f4be 100%);
  border: 2px solid var(--border);
}

.ground {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 88px;
  background:
    radial-gradient(circle at 8% 70%, rgba(124, 183, 110, 0.9) 0 20px, transparent 21px),
    radial-gradient(circle at 26% 72%, rgba(124, 183, 110, 0.7) 0 18px, transparent 19px),
    radial-gradient(circle at 58% 76%, rgba(124, 183, 110, 0.75) 0 22px, transparent 23px),
    radial-gradient(circle at 84% 72%, rgba(124, 183, 110, 0.7) 0 20px, transparent 21px),
    linear-gradient(180deg, #b7e590 0%, #98d36f 100%);
}

.dino,
.egg {
  position: absolute;
  left: 50%;
  bottom: 40px;
  transform-origin: center bottom;
  user-select: none;
  -webkit-user-drag: none;
}

.dino {
  width: 170px;
  transform: translateX(-50%) scale(0.78);
  filter: drop-shadow(0 15px 20px rgba(0,0,0,0.15));
  transition: transform 0.45s ease, left 0.8s ease, opacity 0.35s ease;
}

.egg {
  width: 120px;
  transform: translateX(-50%) scale(1);
  transition: opacity 0.25s ease;
}

.speech {
  position: absolute;
  top: 18px;
  right: 18px;
  max-width: 280px;
  background: rgba(255,255,255,0.93);
  border: 2px solid var(--border);
  border-radius: 20px;
  padding: 12px 14px;
  font-weight: 700;
}

.message-box {
  margin-top: 14px;
  min-height: 64px;
  border: 2px dashed var(--border);
  background: #fbfffb;
  border-radius: 18px;
  padding: 14px;
  font-size: 22px;
  line-height: 1.35;
}

.controls-row {
  margin-top: 14px;
  display: flex;
  gap: 12px;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
}

.checkbox-wrap {
  display: inline-flex;
  gap: 10px;
  align-items: center;
  background: var(--surface-2);
  border: 2px solid var(--border);
  border-radius: 16px;
  padding: 12px 14px;
  font-weight: 700;
}

.checkbox-wrap input {
  width: 24px;
  height: 24px;
}

.secondary-btn,
.confirm-btn {
  padding: 14px 18px;
  background: #edf7ff;
  font-weight: 700;
}

.confirm-btn { background: var(--primary); }

.problem-box {
  background: linear-gradient(180deg, #fffef4 0%, #fffaf0 100%);
  border: 2px solid #f5e1a8;
  border-radius: 24px;
  padding: 18px;
  margin-bottom: 16px;
}

.problem-label {
  color: var(--muted);
  font-weight: 700;
  margin-bottom: 8px;
}

.problem-text {
  font-size: clamp(34px, 5vw, 64px);
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 10px;
}

.problem-hint,
.table-caption {
  color: var(--muted);
  font-size: 17px;
}

.option-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.option-btn {
  min-height: 88px;
  padding: 12px;
  background: #eef8ff;
  border: 2px solid #cfe6f8;
  font-size: clamp(26px, 3.5vw, 36px);
  font-weight: 800;
}

.free-answer {
  display: grid;
  gap: 12px;
}

.free-answer label {
  font-weight: 700;
}

.input-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

#free-answer-input {
  flex: 1;
  min-width: 180px;
  min-height: 64px;
  border-radius: 18px;
  border: 3px solid #cfe6f8;
  padding: 10px 18px;
  font-size: 30px;
  font-weight: 800;
  outline: none;
  background: #fbfeff;
}

#free-answer-input:focus {
  border-color: var(--primary-strong);
  box-shadow: 0 0 0 5px rgba(123, 198, 123, 0.2);
}

.hidden { display: none !important; }

.table-wrap {
  margin-top: 12px;
  overflow: auto;
  border-radius: 20px;
  border: 2px solid var(--border);
}

.math-table {
  width: 100%;
  border-collapse: collapse;
  min-width: 540px;
  background: #fff;
}

.math-table th,
.math-table td {
  border: 1px solid #dfeadd;
  text-align: center;
  padding: 0;
}

.math-table th {
  background: #f4fff0;
  font-size: 21px;
  font-weight: 800;
  width: 66px;
  height: 66px;
}

.table-answer {
  width: 100%;
  min-height: 66px;
  border: none;
  background: white;
  font-size: 24px;
  font-weight: 800;
  cursor: pointer;
}

.highlight-row { background: var(--row-highlight) !important; }
.highlight-col { background: var(--col-highlight) !important; }
.highlight-hit { background: var(--cell-highlight) !important; }

.correct-flash {
  animation: correctFlash 0.55s ease;
}

.wrong-flash {
  animation: wrongFlash 0.55s ease;
}

.run-away {
  left: 115% !important;
  opacity: 0;
}

@keyframes correctFlash {
  0% { transform: scale(1); }
  40% { transform: scale(1.06); }
  100% { transform: scale(1); }
}

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

@media (max-width: 980px) {
  .layout { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  .app-shell { padding: 12px; }
  .card { padding: 14px; border-radius: 22px; }
  .option-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .dino-stage { min-height: 300px; }
  .speech { max-width: 220px; font-size: 14px; }
  .message-box { font-size: 18px; }
}


.problem-text--compact {
  font-size: clamp(24px, 3vw, 34px);
  line-height: 1.35;
  white-space: normal;
}

.mode-select {
  align-items: stretch;
}

@media (max-width: 760px) {
  .mode-btn {
    width: 100%;
  }
}

.header-controls {
  display: flex;
  flex-direction: column;
  gap: 10px;
  align-items: flex-end;
}

.range-select {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.range-title {
  color: var(--muted);
  font-weight: 700;
}

.range-btn {
  border: none;
  border-radius: 14px;
  padding: 10px 14px;
  background: #fff4d8;
  cursor: pointer;
  font-weight: 800;
}

.range-btn.active {
  background: #ffd889;
}

.option-btn--symbol {
  font-size: clamp(40px, 6vw, 64px);
}

.problem-text--compare {
  letter-spacing: 0.08em;
}

@media (max-width: 760px) {
  .header-controls {
    align-items: stretch;
    width: 100%;
  }

  .range-select {
    justify-content: flex-start;
  }
}


.header-controls { display:flex; flex-direction:column; gap:10px; align-items:flex-end; }
.compact-topbar { align-items:flex-start; gap:14px; }
.brand-block { min-width: 280px; }
.compact-header-controls { flex: 1; min-width: 320px; }
.range-select { display:flex; flex-wrap:wrap; gap:10px; align-items:center; justify-content:flex-end; }
.range-title { font-weight:700; color:var(--muted); }
.range-btn {
  border:none; border-radius:16px; padding:10px 16px; font-weight:800; cursor:pointer;
  background:#f0ead1;
}
.range-btn.active { background:#f6cf7d; }
.compact-mode-select {
  display:grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap:8px;
  width:min(760px, 100%);
}
.compact-mode-select .mode-btn {
  padding: 12px 14px;
  min-height: 56px;
  font-size: 15px;
  border-radius: 16px;
}
.option-btn--sequence { min-height: 92px; }
.option-btn--picked { opacity: .65; transform: scale(.98); }
@media (max-width: 1100px) {
  .compact-mode-select { grid-template-columns: repeat(2, minmax(0, 1fr)); width:100%; }
  .header-controls { align-items:stretch; width:100%; }
  .range-select { justify-content:flex-start; }
}
@media (max-width: 720px) {
  .compact-mode-select { grid-template-columns: 1fr; }
}