/* sudoku: rules used only by the sudoku pages (loaded after base.css). */
/* Sudoku board: a 9x9 float-grid (same technique as the chess/checkers/
   Connect Four boards - a JS-enforced square cell size, since CSS
   `aspect-ratio` is unreliable on E-Ink browsers), with a thicker
   border marking each 3x3 box. Given cells are told apart from the
   player's own entries by weight (bold vs regular), and a conflicting
   entry gets a dashed outline - both structural, so nothing here
   depends on color to stay readable on a monochrome E-Ink display. */
#sudoku-board {
  display: block;
  width: 100%;
  max-width: 540px;
  border: 3px solid var(--border);
  background: var(--square-light);
  box-sizing: border-box;
  overflow: hidden;
  margin: 0 auto;
}

.sudoku-cell {
  width: calc(100% / 9);
  background: var(--square-light);
  border: 1px solid var(--border);
}

.sudoku-box-left {
  border-left-width: 3px;
}

.sudoku-box-top {
  border-top-width: 3px;
}

.sudoku-cell-value {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: 1.1rem;
  font-size: clamp(0.9rem, 3.5vw, 1.4rem);
  line-height: 1;
  pointer-events: none;
}

.sudoku-cell-given .sudoku-cell-value {
  font-weight: 700;
}

.sudoku-cell-conflict {
  outline: 2px dashed var(--border);
  outline-offset: -2px;
}

.sudoku-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.4em;
  height: 1.4em;
  border: 2px solid var(--border);
  box-sizing: border-box;
  font-weight: 700;
}