/* ------------------------------------------------------------------
   Sudoku — randolf.dev game styles
   The board is the priority: strong 3x3 separation, light internal
   lines, legible givens/entries/notes. Shared shell comes from
   style.css; this file owns the game surface.
   ------------------------------------------------------------------ */

.sd {
  --sd-line: rgba(236, 236, 240, 0.16);
  --sd-line-strong: rgba(236, 236, 240, 0.55);
  --sd-given: #f4f4f8;
  --sd-entry: var(--accent);
  --sd-note: rgba(236, 236, 240, 0.7);
  --sd-sel: rgba(201, 244, 77, 0.24);
  --sd-peer: rgba(236, 236, 240, 0.05);
  --sd-same: rgba(201, 244, 77, 0.12);
  --sd-conflict: #ff6b6b;
  --sd-hint: #7ed0ff;
  max-width: 32rem;
  margin: 0 auto;
  user-select: none;
  -webkit-user-select: none;
}

.sd .sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.sd [hidden] {
  display: none !important;
}

.sd-page .page-head {
  margin-bottom: clamp(1.5rem, 4vw, 2.25rem);
}

.sd-page .page-title {
  margin: 0.5rem 0 0.9rem;
}

/* ------------------------------------------------------------------
   Top bar — difficulty + hud
   ------------------------------------------------------------------ */

.sd-top {
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 1.1rem;
}

.sd-diff {
  display: inline-flex;
  border: 1px solid var(--line);
  border-radius: 3px;
  overflow: hidden;
}

.sd-diff-btn {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
  background: transparent;
  border: 0;
  border-right: 1px solid var(--line);
  padding: 0.7rem 0.85rem;
  cursor: pointer;
  transition: background 0.15s var(--ease), color 0.15s var(--ease);
  -webkit-tap-highlight-color: transparent;
}

.sd-diff-btn:last-child {
  border-right: 0;
}

.sd-diff-btn:hover {
  color: var(--fg);
}

.sd-diff-btn[aria-pressed="true"] {
  background: var(--accent);
  color: var(--accent-ink);
}

.sd-diff-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

.sd-hud {
  display: flex;
  gap: 0.6rem;
}

.sd-stat {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 0.25rem;
  min-width: 4.6rem;
  padding: 0.5rem 0.8rem;
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: 3px;
}

.sd-stat .mono {
  font-size: 9px;
}

.sd-stat-value {
  font-size: 14px;
  letter-spacing: 0.05em;
  color: var(--fg);
}

/* ------------------------------------------------------------------
   Board
   ------------------------------------------------------------------ */

.sd-stage {
  display: flex;
  justify-content: center;
  margin-bottom: 0.85rem;
}

.sd-board-wrap {
  position: relative;
  width: 100%;
}

.sd-board {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  grid-template-rows: repeat(9, 1fr);
  aspect-ratio: 1 / 1;
  border: 2px solid var(--sd-line-strong);
  border-radius: 2px;
  background: var(--bg-2);
  overflow: hidden;
}

.sd-board.is-complete {
  box-shadow: 0 0 0 1px var(--accent), 0 0 28px rgba(201, 244, 77, 0.28);
  transition: box-shadow 0.5s var(--ease);
}

.sd-cell {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  margin: 0;
  min-width: 0;
  font: inherit;
  color: inherit;
  background: transparent;
  border: 0;
  border-right: 1px solid var(--sd-line);
  border-bottom: 1px solid var(--sd-line);
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  transition: background 0.12s linear;
}

/* 3x3 box separation */
.sd-cell:nth-child(9n + 3),
.sd-cell:nth-child(9n + 6) {
  border-right: 2px solid var(--sd-line-strong);
}

.sd-cell:nth-child(9n) {
  border-right: 0;
}

.sd-cell:nth-child(n + 19):nth-child(-n + 27),
.sd-cell:nth-child(n + 46):nth-child(-n + 54) {
  border-bottom: 2px solid var(--sd-line-strong);
}

.sd-cell:nth-child(n + 73) {
  border-bottom: 0;
}

.sd-cell:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
  z-index: 3;
}

.sd-val {
  font-size: clamp(1rem, 5vw, 1.9rem);
  line-height: 1;
  font-variant-numeric: tabular-nums;
  transition: color 0.12s linear;
}

.sd-cell.is-given .sd-val {
  color: var(--sd-given);
  font-weight: 700;
}

.sd-cell.is-entry .sd-val {
  color: var(--sd-entry);
  font-weight: 500;
}

.sd-notes {
  position: absolute;
  inset: 7%;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
}

.sd-notes i {
  display: flex;
  align-items: center;
  justify-content: center;
  font-style: normal;
  font-size: clamp(0.52rem, 2.1vw, 0.78rem);
  line-height: 1;
  color: var(--sd-note);
  font-variant-numeric: tabular-nums;
}

.sd-notes i[hidden] {
  visibility: hidden;
}

/* Highlight layers — peers subtle, selection dominant */
.sd-cell.is-peer {
  background: var(--sd-peer);
}

.sd-cell.is-same {
  background: var(--sd-same);
}

.sd-cell.is-conflict {
  background: rgba(255, 107, 107, 0.16);
}

.sd-cell.is-conflict .sd-val {
  color: var(--sd-conflict);
}

.sd-cell.is-sel {
  background: var(--sd-sel);
  box-shadow: inset 0 0 0 2px var(--accent);
  z-index: 2;
}

.sd-cell.is-sel .sd-notes i {
  color: var(--fg);
}

.sd-cell.is-hint {
  box-shadow: inset 0 0 0 2px var(--sd-hint);
  z-index: 2;
}

.sd-cell.is-hint-pulse {
  animation: sd-pulse 1.1s var(--ease) infinite;
}

.sd-cell.is-hint i {
  color: var(--sd-hint);
}

/* Answer checks are transient and leave the normal conflict layer intact. */
.sd-cell.is-check-error {
  animation: sd-check-cell 300ms linear 3;
}

.sd-cell.is-check-error .sd-val {
  animation: sd-check-digit 300ms linear 3;
}

@keyframes sd-check-cell {
  25%, 60% { background: rgba(255, 107, 107, 0.42); }
}

@keyframes sd-check-digit {
  25%, 60% { color: var(--sd-conflict); }
}

/* Victory sweep — one restrained 3x3 box stagger */
.sd-board.is-complete .sd-cell {
  animation: sd-box-in 0.42s var(--ease) both;
  animation-delay: calc(var(--sd-b, 0) * 45ms);
}

@keyframes sd-pulse {
  0%, 100% { background: rgba(126, 208, 255, 0.06); }
  50% { background: rgba(126, 208, 255, 0.22); }
}

@keyframes sd-box-in {
  from { background: rgba(201, 244, 77, 0.32); }
  to { background: transparent; }
}

/* ------------------------------------------------------------------
   Overlays
   ------------------------------------------------------------------ */

.sd-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  background: rgba(10, 10, 12, 0.86);
  backdrop-filter: blur(2px);
  border: 2px solid var(--line);
  z-index: 5;
}

.sd-panel {
  text-align: center;
  max-width: 22rem;
}

.sd-panel-eyebrow {
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.sd-panel-title {
  font-size: clamp(1.4rem, 5vw, 2rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  text-transform: uppercase;
  margin-bottom: 0.8rem;
}

.sd-panel-note {
  color: var(--muted);
  margin-bottom: 1rem;
}

.sd-panel-note strong {
  color: var(--fg);
}

.sd-panel-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: center;
}

.sd-spinner {
  display: inline-block;
  width: 14px;
  height: 14px;
  margin-right: 0.5rem;
  border: 2px solid var(--line);
  border-top-color: var(--accent);
  border-radius: 50%;
  vertical-align: -2px;
  animation: sd-spin 0.8s linear infinite;
}

@keyframes sd-spin {
  to { transform: rotate(360deg); }
}

/* ------------------------------------------------------------------
   Feedback + controls
   ------------------------------------------------------------------ */

.sd-feedback {
  min-height: 1.4em;
  margin-bottom: 0.9rem;
  color: var(--muted);
  text-align: center;
}

.sd-feedback.is-note {
  color: var(--sd-hint);
}

.sd-feedback.is-warn {
  color: var(--sd-conflict);
}

.sd-pad {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  gap: 6px;
  margin-bottom: 0.6rem;
}

.sd-key {
  position: relative;
  font-family: var(--mono);
  font-size: clamp(0.95rem, 4.2vw, 1.15rem);
  color: var(--fg);
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: 3px;
  min-height: 48px;
  cursor: pointer;
  transition: border-color 0.15s var(--ease), color 0.15s var(--ease),
    background 0.15s var(--ease);
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
}

.sd-key:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.sd-key.is-done {
  opacity: 0.32;
}

.sd-key:focus-visible,
.sd-btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.sd-key .sd-key-count {
  position: absolute;
  right: 4px;
  bottom: 2px;
  font-size: 8px;
  color: var(--muted);
}

.sd-actions {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 6px;
  margin-bottom: 0.6rem;
}

.sd-actions-puzzle {
  grid-template-columns: repeat(3, 1fr);
}

.sd-btn {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--fg);
  background: transparent;
  border: 1px solid var(--line);
  border-radius: 3px;
  padding: 0.7rem 0.6rem;
  min-height: 44px;
  cursor: pointer;
  transition: border-color 0.15s var(--ease), color 0.15s var(--ease),
    background 0.15s var(--ease);
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
}

.sd-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.sd-btn:disabled {
  opacity: 0.35;
  cursor: default;
}

.sd-btn:disabled:hover {
  border-color: var(--line);
  color: var(--fg);
}

.sd-btn.is-active {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-ink);
}

.sd-btn.is-active:hover {
  color: var(--accent-ink);
}

.sd-btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-ink);
}

.sd-btn-primary:hover {
  color: var(--accent-ink);
  filter: brightness(1.08);
}

/* ------------------------------------------------------------------
   Responsive — phone first-class
   ------------------------------------------------------------------ */

@media (max-width: 520px) {
  .sd-actions:not(.sd-actions-puzzle) {
    grid-template-columns: repeat(6, 1fr);
  }

  .sd-actions:not(.sd-actions-puzzle) .sd-btn {
    grid-column: span 2;
  }

  .sd-actions:not(.sd-actions-puzzle) [data-sd-hint] {
    grid-column: 2 / span 2;
  }

  .sd-pad {
    grid-template-columns: repeat(3, 1fr);
  }

  .sd-key {
    min-height: 50px;
  }

  .sd-stat {
    min-width: 4rem;
    padding: 0.4rem 0.65rem;
  }
}

@media (max-width: 360px) {
  .sd-actions {
    gap: 4px;
  }

  .sd-btn {
    font-size: 9px;
    letter-spacing: 0.08em;
    padding: 0.6rem 0.35rem;
  }
}

/* ------------------------------------------------------------------
   Reduced motion
   ------------------------------------------------------------------ */

@media (prefers-reduced-motion: reduce) {
  .sd-cell,
  .sd-val,
  .sd-key,
  .sd-btn,
  .sd-diff-btn {
    transition-duration: 0.01ms !important;
  }

  .sd-cell.is-hint-pulse {
    animation: none;
    background: rgba(126, 208, 255, 0.16);
  }

  .sd-cell.is-check-error {
    animation: none;
    background: rgba(255, 107, 107, 0.42);
  }

  .sd-cell.is-check-error .sd-val {
    animation: none;
    color: var(--sd-conflict);
  }

  .sd-board.is-complete .sd-cell {
    animation: none;
  }

  .sd-board.is-complete {
    box-shadow: 0 0 0 1px var(--accent);
  }

  .sd-spinner {
    animation-duration: 1.4s;
  }
}