:root {
  --cell-size: 52px;
  --gap: 2px;
  --radius: 6px;
  --color-1: #f9a8d4;
  --color-2: #c4b5fd;
  --color-3: #a5b4fc;
  --color-4: #6ee7b7;
  --color-5: #fcd34d;
  --color-6: #fdba74;
  --color-7: #86efac;
  --color-8: #7dd3fc;
  --color-9: #f0abfc;
  --color-10: #a78bfa;
  --color-11: #34d399;
  --color-12: #60a5fa;
  --color-13: #fb923c;
  --color-14: #f472b6;
  --color-15: #4ade80;
  --color-16: #38bdf8;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: system-ui, sans-serif;
  background: #f8fafc;
  color: #1e293b;
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: flex-start;
}

/* ── Mobile (default) ── */
#app {
  width: 100%;
  max-width: 480px;
  padding: 16px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

#left-panel {
  display: contents; /* transparent wrapper on mobile */
}

header { text-align: center; }
#game-title { font-size: clamp(1.2rem, 5vw, 1.8rem); font-weight: 700; }
#level-label { font-size: 0.9rem; color: #64748b; margin-top: 4px; }

#rules-bar {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: center;
  font-size: 0.8rem;
  color: #475569;
}

#rules-bar span {
  background: #e2e8f0;
  border-radius: 12px;
  padding: 4px 10px;
}

#controls {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  width: 100%;
}

#remaining-display {
  font-size: 1rem;
  font-weight: 600;
}

#mode-buttons {
  display: flex;
  gap: 8px;
}

#mode-buttons button, #btn-hint {
  min-width: 44px;
  min-height: 44px;
  padding: 8px 16px;
  border: 2px solid #cbd5e1;
  border-radius: 8px;
  background: #fff;
  cursor: pointer;
  font-size: 0.95rem;
  transition: background 0.15s, border-color 0.15s;
}

#mode-buttons button.active {
  background: #dbeafe;
  border-color: #3b82f6;
}

#btn-hint {
  background: #fff;
  border-color: #f59e0b;
  color: #92400e;
}

#btn-hint:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

#pc-hint {
  display: none;
  font-size: 0.85rem;
  color: #64748b;
}

/* Level nav (PC only) */
#level-nav {
  display: none;
}

.level-nav-btn {
  width: 36px;
  height: 36px;
  border: 2px solid #cbd5e1;
  border-radius: 8px;
  background: #fff;
  cursor: pointer;
  font-size: 1.2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s;
}

.level-nav-btn:hover:not(:disabled) { background: #f1f5f9; }
.level-nav-btn:disabled { opacity: 0.35; cursor: not-allowed; }

#level-nav-label {
  font-size: 0.9rem;
  font-weight: 600;
  min-width: 72px;
  text-align: center;
  color: #334155;
}

/* Level selector (mobile only) */
#level-selector {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  justify-content: center;
}

.level-btn {
  min-width: 44px;
  min-height: 44px;
  padding: 8px 12px;
  border: 2px solid #cbd5e1;
  border-radius: 8px;
  background: #fff;
  cursor: pointer;
  font-size: 0.9rem;
  transition: background 0.15s;
}

.level-btn.active { background: #dbeafe; border-color: #3b82f6; }
.level-btn:disabled { opacity: 0.35; cursor: not-allowed; }

/* Grid */
#grid-container {
  display: grid;
  gap: var(--gap);
}

.grid-cell {
  width: var(--cell-size);
  height: var(--cell-size);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: calc(var(--cell-size) * 0.55);
  border-radius: var(--radius);
  cursor: pointer;
  user-select: none;
  position: relative;
  transition: transform 0.1s;
  border: 2px solid transparent;
  box-shadow: inset 0 0 0 1px rgba(0,0,0,0.08);
}

.grid-cell:active { transform: scale(0.93); }

.grid-cell[data-state="excluded"]::after {
  content: '✕';
  font-size: calc(var(--cell-size) * 0.4);
  color: #64748b;
}

.grid-cell[data-state="cow"]::after,
.grid-cell[data-state="locked-cow"]::after {
  content: '🐄';
  animation: bounce-in 0.2s ease;
}

.grid-cell[data-state="locked-cow"] .lock-icon {
  position: absolute;
  bottom: 2px;
  right: 2px;
  font-size: calc(var(--cell-size) * 0.25);
  line-height: 1;
}

.grid-cell.error {
  border-color: #ef4444;
  background-color: rgba(239, 68, 68, 0.18) !important;
}

/* Color regions */
.grid-cell[data-color="1"]  { background: var(--color-1); }
.grid-cell[data-color="2"]  { background: var(--color-2); }
.grid-cell[data-color="3"]  { background: var(--color-3); }
.grid-cell[data-color="4"]  { background: var(--color-4); }
.grid-cell[data-color="5"]  { background: var(--color-5); }
.grid-cell[data-color="6"]  { background: var(--color-6); }
.grid-cell[data-color="7"]  { background: var(--color-7); }
.grid-cell[data-color="8"]  { background: var(--color-8); }
.grid-cell[data-color="9"]  { background: var(--color-9); }
.grid-cell[data-color="10"] { background: var(--color-10); }
.grid-cell[data-color="11"] { background: var(--color-11); }
.grid-cell[data-color="12"] { background: var(--color-12); }
.grid-cell[data-color="13"] { background: var(--color-13); }
.grid-cell[data-color="14"] { background: var(--color-14); }
.grid-cell[data-color="15"] { background: var(--color-15); }
.grid-cell[data-color="16"] { background: var(--color-16); }

/* Victory modal */
#victory-modal {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
}

#victory-modal[hidden] { display: none; }

#victory-content {
  background: #fff;
  border-radius: 16px;
  padding: 32px;
  text-align: center;
  max-width: 300px;
  animation: pop-in 0.3s ease;
}

@keyframes pop-in {
  from { transform: scale(0.8); opacity: 0; }
  to   { transform: scale(1);   opacity: 1; }
}

@keyframes bounce-in {
  0%   { transform: scale(0.5); opacity: 0; }
  60%  { transform: scale(1.2); }
  100% { transform: scale(1); opacity: 1; }
}

#victory-title { font-size: 1.5rem; margin-bottom: 8px; }
#victory-message { color: #475569; margin-bottom: 20px; }
#btn-next-level {
  padding: 10px 24px;
  background: #3b82f6;
  color: #fff;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
}

/* ── PC layout ── */
@media (hover: hover) and (pointer: fine) {
  body {
    align-items: center;
  }

  #app {
    flex-direction: row;
    align-items: center;
    max-width: 960px;
    min-height: 100vh;
    padding: 40px 48px;
    gap: 56px;
  }

  #left-panel {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 20px;
    width: 220px;
    flex-shrink: 0;
  }

  header { text-align: left; }

  #rules-bar {
    flex-direction: column;
    justify-content: flex-start;
    gap: 6px;
  }

  #controls {
    align-items: flex-start;
  }

  #btn-hint {
    width: 100%;
  }

  #mode-buttons { display: none; }
  #pc-hint { display: block; }

  #level-nav {
    display: flex;
    align-items: center;
    gap: 10px;
  }

  #level-selector { display: none; }

  #grid-container {
    flex: 1;
    align-self: center;
    justify-self: center;
  }
}