.sdk-game {
  max-width: 480px;
  margin: 0 auto;
  text-align: center;
  --sdk-given-bg: rgba(42, 26, 14, 0.06);
  --sdk-given-ring: rgba(42, 26, 14, 0.10);
  --sdk-user-bg: rgba(43, 94, 163, 0.12);
  --sdk-user-ring: rgba(43, 94, 163, 0.18);
  --sdk-user-text: #1f4f91;
}

[data-theme="dark"] .sdk-game {
  --sdk-given-bg: rgba(232, 221, 208, 0.08);
  --sdk-given-ring: rgba(232, 221, 208, 0.12);
  --sdk-user-bg: rgba(109, 179, 242, 0.16);
  --sdk-user-ring: rgba(109, 179, 242, 0.24);
  --sdk-user-text: #8bc7ff;
}

/* ── Board Wrap (positioning context for overlay) ── */

.sdk-board-wrap {
  position: relative;
}

/* ── Difficulty Picker Overlay ── */

.sdk-picker {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.35);
  border-radius: 4px;
  z-index: 10;
}

.sdk-picker[hidden] {
  display: none;
}

.sdk-picker-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.5rem 2rem;
  text-align: center;
}

.sdk-picker-label {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--heading);
  margin: 0 0 1rem;
}

.sdk-picker-options {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
}

.sdk-picker-btn {
  padding: 0.6rem 1.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--code-bg);
  color: var(--text);
  font: inherit;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
}

.sdk-picker-btn:hover {
  background: var(--link);
  border-color: var(--link);
  color: #fff;
}

.sdk-timer {
  font-size: 0.9rem;
  color: var(--meta);
  font-variant-numeric: tabular-nums;
  margin-bottom: 0.75rem;
}

/* ── Board ── */

.sdk-board {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  border: 2px solid var(--heading);
  border-radius: 4px;
  overflow: hidden;
  margin-bottom: 1rem;
}

.sdk-cell {
  aspect-ratio: 1;
  background: var(--bg);
  border: 1px solid var(--border);
  font-size: 1.4rem;
  font-weight: 700;
  line-height: 1;
  cursor: pointer;
  color: var(--heading);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  position: relative;
}

/* 3x3 box borders — thicker lines every 3 cells */
.sdk-cell[data-sdk-col="3"],
.sdk-cell[data-sdk-col="6"] {
  border-left: 2px solid var(--heading);
}
.sdk-cell[data-sdk-row="3"],
.sdk-cell[data-sdk-row="6"] {
  border-top: 2px solid var(--heading);
}

.sdk-cell:hover:not([disabled]):not(.sdk-selected-num) {
  background: var(--code-bg);
}

.sdk-cell[disabled] {
  cursor: default;
  opacity: 1;
}

.sdk-cell.sdk-given {
  color: var(--heading);
  font-weight: 800;
  background: var(--sdk-given-bg);
  box-shadow: inset 0 0 0 1px var(--sdk-given-ring);
}

.sdk-cell.sdk-user {
  color: var(--sdk-user-text);
  background: var(--sdk-user-bg);
  box-shadow: inset 0 0 0 1px var(--sdk-user-ring);
}

.sdk-cell.sdk-selected-num {
  background: var(--link);
  color: #fff !important;
}

.sdk-cell.sdk-highlight-line {
  background: rgba(139, 94, 60, 0.10);
}

[data-theme="dark"] .sdk-cell.sdk-highlight-line {
  background: rgba(196, 154, 108, 0.12);
}

.sdk-cell.sdk-error {
  color: #c0392b;
  background: rgba(192, 57, 43, 0.08);
}

.sdk-cell.sdk-complete {
  background: rgba(39, 174, 96, 0.08);
}

/* ── Pencil marks ── */

.sdk-notes-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
}

.sdk-note {
  font-size: clamp(0.35rem, 1.2vw, 0.55rem);
  line-height: 1;
  color: var(--meta);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ── Number bar ── */

.sdk-numbar {
  display: flex;
  gap: 4px;
  justify-content: center;
  margin-bottom: 1rem;
}

.sdk-num-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.sdk-num-count {
  font-size: 0.65rem;
  color: var(--meta);
  font-weight: 700;
  line-height: 1;
  min-height: 0.65rem;
}

.sdk-num {
  width: 2.4rem;
  height: 2.4rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--code-bg);
  color: var(--text);
  font: inherit;
  font-size: 1.1rem;
  font-weight: 700;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}

.sdk-num:hover {
  background: var(--link);
  border-color: var(--link);
  color: #fff;
}

.sdk-num.sdk-active {
  background: var(--link);
  border-color: var(--link);
  color: #fff;
}

.sdk-num.sdk-num-complete {
  opacity: 0.3;
}

.sdk-erase {
  font-size: 1.3rem;
}

/* ── Controls ── */

.sdk-controls {
  display: flex;
  gap: 0.5rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.sdk-btn {
  padding: 0.45rem 1rem;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--code-bg);
  color: var(--text);
  font: inherit;
  font-size: 0.85rem;
  font-weight: 700;
  cursor: pointer;
}

.sdk-btn:hover {
  background: var(--link);
  border-color: var(--link);
  color: #fff;
}

.sdk-btn.sdk-active {
  background: var(--link);
  border-color: var(--link);
  color: #fff;
}

/* ── Picking State (controls disabled while overlay is open) ── */

.sdk-picking .sdk-numbar,
.sdk-picking .sdk-controls,
.sdk-picking .sdk-timer {
  opacity: 0.35;
  pointer-events: none;
}

/* ── Status ── */

.sdk-status {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--heading);
  min-height: 1.6em;
}

/* ── Responsive ── */

@media (max-width: 420px) {
  .sdk-game {
    max-width: 100%;
  }

  .sdk-cell {
    font-size: 1.1rem;
  }

  .sdk-num {
    width: 2rem;
    height: 2rem;
    font-size: 0.95rem;
  }

  .sdk-btn {
    padding: 0.4rem 0.7rem;
    font-size: 0.8rem;
  }
}