.sk-difficulty {
  display: flex;
  gap: 6px;
  margin: 12px 0 0;
  padding: 4px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 12px;
}
.sk-diff {
  flex: 1;
  padding: 8px 10px;
  border-radius: 8px;
  border: 1px solid transparent;
  background: transparent;
  color: var(--fg-dim);
  font-weight: 600;
  font-size: 14px;
  cursor: pointer;
  transition: background 0.1s ease, color 0.1s ease, border-color 0.1s ease;
}
.sk-diff[aria-selected="true"] {
  background: var(--bg-elev-2);
  color: var(--fg);
  border-color: var(--border);
  box-shadow: var(--shadow-card);
}
@media (hover: hover) {
  .sk-diff:hover:not([aria-selected="true"]) { color: var(--fg); }
}

.statbar .middle {
  display: flex;
  flex-direction: column;
  align-items: center;
  flex: 1;
  text-align: center;
}

.sk-board {
  --cell-size: clamp(30px, calc((100vw - 36px) / 9), 48px);
  display: grid;
  grid-template-columns: repeat(9, var(--cell-size));
  grid-template-rows: repeat(9, var(--cell-size));
  margin: 16px auto 0;
  width: max-content;
  background: var(--bg-elev);
  border: 2px solid var(--fg);
  border-radius: 6px;
  overflow: hidden;
  user-select: none;
  -webkit-user-select: none;
  touch-action: manipulation;
}

.sk-cell {
  width: var(--cell-size);
  height: var(--cell-size);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--mono);
  font-size: calc(var(--cell-size) * 0.5);
  font-weight: 500;
  font-variant-numeric: tabular-nums;
  color: var(--fg);
  background: var(--bg-elev);
  border: 1px solid var(--border-soft);
  cursor: pointer;
  transition: background 0.08s ease, color 0.08s ease;
  position: relative;
}
/* Thicker borders between 3x3 boxes */
.sk-cell[data-col="3"], .sk-cell[data-col="6"] { border-left-color: var(--fg); border-left-width: 2px; }
.sk-cell[data-row="3"], .sk-cell[data-row="6"] { border-top-color: var(--fg); border-top-width: 2px; }

.sk-cell.given {
  font-weight: 700;
  color: var(--fg);
  background: var(--bg-soft);
  cursor: default;
}
.sk-cell.user { color: var(--accent); }
.sk-cell.peer { background: var(--accent-soft); }
.sk-cell.match { background: rgba(29, 78, 216, 0.18); }
.sk-cell.selected {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
  z-index: 1;
}
.sk-cell.given.peer { background: color-mix(in srgb, var(--bg-soft) 70%, var(--accent) 12%); }

.sk-pad {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 6px;
  margin: 14px auto 0;
  max-width: 480px;
}
.sk-key {
  padding: 12px 0;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--fg);
  font-family: var(--mono);
  font-size: 18px;
  font-weight: 600;
  cursor: pointer;
  min-height: 44px;
}
.sk-key:active { background: var(--bg-elev-2); }
.sk-key.sk-erase { font-family: var(--sans); font-size: 16px; color: var(--fg-dim); }
.sk-key.exhausted { color: var(--fg-faint); background: var(--bg-soft); }
@media (hover: hover) {
  .sk-key:hover:not(.exhausted) { border-color: var(--accent); }
}

.controls { margin-top: 14px; }

.sk-board.solved .sk-cell.user { color: var(--accent-3); }
.sk-board.solved { border-color: var(--accent-3); }

@media (max-width: 380px) {
  .sk-board {
    --cell-size: clamp(28px, calc((100vw - 24px) / 9), 40px);
  }
  .sk-key { padding: 10px 0; font-size: 16px; }
}