/* ============================================================
   board.css: the chessboard and the widgets wrapped around it
   ============================================================ */

.board {
  width: 100%;
  max-width: var(--board-max, 30rem);
  aspect-ratio: 1 / 1;
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
  container-type: inline-size;
  border-radius: 6px;
  overflow: hidden;
  box-shadow: 0 2px 0 rgba(0, 0, 0, 0.18), 0 10px 24px -12px rgba(0, 0, 0, 0.5);
  border: 3px solid var(--board-frame);
  background: var(--sq-dark);
  touch-action: manipulation;
}

.sq {
  position: relative;
  display: grid;
  place-items: center;
  padding: 0;
  margin: 0;
  border: 0;
  border-radius: 0;
  font: inherit;
  cursor: pointer;
  appearance: none;
  -webkit-tap-highlight-color: transparent;
}
.sq.light { background: var(--sq-light); }
.sq.dark  { background: var(--sq-dark); }
.sq.static { cursor: default; }

.sq:focus-visible {
  outline: 3px solid var(--focus-board);
  outline-offset: -3px;
  z-index: 4;
}

/* --- pieces ------------------------------------------------ */

.pc {
  font-family: var(--font-chess);
  font-size: 2rem;                 /* fallback for old browsers */
  font-size: 10.5cqw;
  line-height: 1;
  user-select: none;
  pointer-events: none;
  transition: transform 260ms cubic-bezier(0.22, 0.7, 0.3, 1);
  /* No will-change here. It looks like a free hint, but it pins a GPU
     layer per piece for the life of the page: 64 squares times up to 15
     boards is ~960 permanent backing stores, which is enough for Safari
     to reload the tab for "using significant memory". The slide is one
     short transform and gets its layer on demand. */
  z-index: 2;
  /* Draw the outline BEHIND the fill. Without this the dark stroke eats
     into the white pieces and both armies end up looking black. */
  paint-order: stroke fill;
}
.pc.white {
  color: #fff;
  -webkit-text-stroke: 0.045em #2a2724;
  text-shadow: 0 0.03em 0.02em rgba(0, 0, 0, 0.4);
}
.pc.black {
  color: #2a2724;
  -webkit-text-stroke: 0.02em #14120f;
  text-shadow: 0 0.03em 0.02em rgba(255, 255, 255, 0.18);
}

/* --- coordinates ------------------------------------------- */

.coord {
  position: absolute;
  font-size: 0.6rem;
  font-size: 3cqw;
  font-weight: 700;
  line-height: 1;
  opacity: 0.75;
  pointer-events: none;
  z-index: 3;
}
.coord-file { bottom: 4%; right: 6%; }
.coord-rank { top: 4%; left: 6%; }
.sq.light .coord { color: var(--sq-dark); }
.sq.dark .coord { color: var(--sq-light); }

/* --- highlights -------------------------------------------- */

/* A quiet move: a dot in the middle of the square. */
.sq.is-move::after {
  content: "";
  position: absolute;
  inset: 36%;
  border-radius: 50%;
  background: rgba(20, 106, 70, 0.62);
  z-index: 1;
}
/* A capture: a ring around the piece you can take. */
.sq.is-capture::after {
  content: "";
  position: absolute;
  inset: 4%;
  border-radius: 50%;
  border: 0.42em solid rgba(184, 58, 43, 0.55);
  box-sizing: border-box;
  z-index: 1;
}
.sq.light.is-last { background: var(--sq-light-mark); }
.sq.dark.is-last  { background: var(--sq-dark-mark); }
.sq.light.is-selected { background: var(--sq-light-pick); }
.sq.dark.is-selected  { background: var(--sq-dark-pick); }
.sq.is-good     { box-shadow: inset 0 0 0 100vmax rgba(46, 168, 108, 0.55); }
.sq.is-bad      { box-shadow: inset 0 0 0 100vmax rgba(200, 66, 50, 0.5); }
.sq.is-check::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle, rgba(220, 60, 45, 0.85) 12%, rgba(220, 60, 45, 0) 72%);
  z-index: 1;
}
.sq.is-hint {
  animation: hint-pulse 1.1s ease-in-out infinite;
}
@keyframes hint-pulse {
  0%, 100% { box-shadow: inset 0 0 0 0.35em rgba(5, 18, 46, 0); }
  50%      { box-shadow: inset 0 0 0 0.35em rgba(5, 18, 46, 0.85); }
}

.board.shake { animation: board-shake 380ms ease; }
@keyframes board-shake {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-6px); }
  40% { transform: translateX(6px); }
  60% { transform: translateX(-4px); }
  80% { transform: translateX(4px); }
}

@media (prefers-reduced-motion: reduce) {
  .pc { transition: none; }
  .board.shake { animation: none; }
  .sq.is-hint { animation: none; box-shadow: inset 0 0 0 0.35em rgba(5, 18, 46, 0.85); }
}

/* ============================================================
   Widget chrome: board on the left, words and buttons beside it
   ============================================================ */

.board-widget {
  margin: 1.75rem 0;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--card);
  display: grid;
  gap: 1rem 1.25rem;
  grid-template-columns: 1fr;
  align-items: start;
}
@media (min-width: 46rem) {
  .board-widget { grid-template-columns: minmax(0, 22rem) minmax(0, 1fr); }
}

.board-widget > figcaption {
  grid-column: 1 / -1;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--accent);
  margin-bottom: -0.25rem;
}

/* Marks a puzzle the player has already cracked. */
.solved-badge {
  margin-left: auto;
  flex: none;
  font-family: var(--font-ui);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--on-good);
  background: var(--good);
  border-radius: 999px;
  padding: 0.15rem 0.7rem 0.2rem;
}
.solved-badge::before {
  content: "\2713\00a0";
}
.solved-badge[hidden] { display: none; }

.board-widget.is-solved {
  border-color: var(--good);
  box-shadow: inset 0.28rem 0 0 var(--good);
}

.board-side {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  min-width: 0;
}

.board-status {
  margin: 0;
  min-height: 3.2em;
  font-size: 1rem;
  line-height: 1.45;
}
.board-status .tag {
  display: inline-block;
  font-weight: 700;
  color: var(--accent);
}
.board-status.good { color: var(--good); font-weight: 600; }
.board-status.bad  { color: var(--bad); font-weight: 600; }

.board-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.btn {
  /* Set the family here rather than with `font: inherit`, which would
     undo the interface typeface site.css gives buttons. */
  font-family: var(--font-ui);
  font-size: 0.95rem;
  font-weight: 600;
  padding: 0.5rem 0.95rem;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--paper);
  color: var(--ink);
  cursor: pointer;
  min-height: 2.75rem;
  transition: background 120ms ease, transform 80ms ease;
}
.btn:hover { background: var(--hover); }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: 0.4; cursor: default; }
.btn:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }
.btn.primary { background: var(--accent); color: var(--on-accent); border-color: var(--accent); }
.btn.primary:hover { background: var(--accent-dark); }

.move-list {
  margin: 0;
  padding: 0.6rem 0.75rem;
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem 0.5rem;
  background: var(--paper);
  border-radius: 10px;
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 0.92rem;
  max-height: 9rem;
  overflow-y: auto;
}
.move-list li { padding: 0.1rem 0.3rem; border-radius: 5px; }
.move-list li.num { opacity: 0.55; }
.move-list li.current { background: var(--accent); color: var(--on-accent); font-weight: 700; }

.board-legend {
  font-size: 0.9rem;
  opacity: 0.8;
  margin: 0;
}

.board-goal {
  margin: 0;
  font-weight: 700;
  color: var(--accent);
}

.progress {
  height: 0.6rem;
  border-radius: 999px;
  background: var(--line);
  overflow: hidden;
}
.progress > span {
  display: block;
  height: 100%;
  background: var(--accent);
  transition: width 300ms ease;
}