.board-cross {
  display: grid;
  gap: 2px;
  box-sizing: border-box;
  width: 100%;
  max-width: min(92vw, 22rem);
  margin-inline: auto;
  container-type: inline-size;
  /* Set on the board so cqw is the full grid width; numerals use 1em (see play-shell.css). */
  font-size: clamp(
    0.85rem,
    calc(100cqw / var(--cross-dim, 7) * 0.58),
    2.5rem
  );
  --cross-num-font: 1em;
}
.board-cross .cell.cross-num {
  position: relative;
  display: grid;
  place-items: center;
  box-sizing: border-box;
  min-width: 0;
  min-height: 0;
  aspect-ratio: 1;
  border: 0;
  border-top: 1px solid var(--board-line);
  border-left: 1px solid var(--board-line);
  background: var(--board-cell, #fffaf0);
  font-weight: var(--weight-entry, 500);
  color: var(--board-entry, #2438c9);
}
.board-cross .cell.cross-num.is-given {
  color: var(--board-given, #140f0a);
  font-weight: var(--weight-given, 800);
}
.board-cross .cell.cross-num.is-selected {
  z-index: 2;
  background-color: var(--board-cell-sel);
  box-shadow: inset 0 0 0 2.5px var(--play-ring-active, #19D65A);
}
.board-cross .op,
.board-cross .pad {
  display: grid;
  place-items: center;
  min-height: 0;
  min-width: 0;
  padding: 0 1px;
  font-size: clamp(1.125rem, 5.625vw, 1.5625rem);
  line-height: 1;
  font-weight: 700;
}
.board-cross .result {
  display: grid;
  place-items: center;
  box-sizing: border-box;
  min-width: 0;
  min-height: 0;
  padding: 0 2px;
  line-height: 1;
  font-weight: 800;
  white-space: nowrap;
  aspect-ratio: 1;
  color: var(--ink, #140f0a);
  background: color-mix(in srgb, #edf0df 72%, var(--board-cell, #fffaf0));
  border: 1px solid color-mix(in srgb, var(--board-line, #c8c4b8) 55%, transparent);
  border-radius: var(--radius-sm, 6px);
}
.board-cross .op,
.board-cross .pad {
  color: color-mix(in srgb, var(--ink, #140f0a) 72%, #6b6358);
  background: transparent;
}
.board-cross .op.eq {
  font-weight: 800;
}