.ink-board {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2px;
  padding: 2px;
  background: #1a1714;
  border-radius: 4px;
  aspect-ratio: 1;
  width: 100%;
}

.ink-box {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: #c8c0b2;
}

.ink-cell {
  background: #fff;
  display: grid;
  place-items: center;
  font-variant-numeric: tabular-nums;
  font-weight: 650;
  font-size: clamp(12px, 2.4vw, 22px);
  color: #1a1714;
  min-height: 0;
}

.ink-cell.is-answer {
  color: #5c564e;
  font-weight: 500;
}

.paper {
  background: #fff;
  color: #1a1714;
  box-shadow: var(--shadow);
  border-radius: 4px;
  margin: 0 auto 28px;
  padding: 14mm 14mm 12mm;
  width: min(100%, 210mm);
  min-height: 297mm;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

html[data-paper="letter"] .paper {
  width: min(100%, 8.5in);
  min-height: 11in;
}

.paper-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  border-bottom: 1.5px solid #1a1714;
  padding-bottom: 8px;
}

.paper-brand {
  font-family: var(--font-display);
  font-size: 22px;
  letter-spacing: -0.04em;
}

.paper-brand em {
  font-style: italic;
  color: #0f6e63;
}

.paper-meta {
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #6f675e;
}

.paper-puzzles {
  display: grid;
  gap: 16px 20px;
  flex: 1;
  align-content: start;
}

.paper[data-per="1"] .paper-puzzles {
  grid-template-columns: 1fr;
  max-width: 150mm;
  margin: 12px auto 0;
  width: 100%;
}

.paper[data-per="2"] .paper-puzzles {
  grid-template-columns: 1fr;
  max-width: 130mm;
  margin: 0 auto;
  width: 100%;
}

.paper[data-per="4"] .paper-puzzles,
.paper[data-per="6"] .paper-puzzles {
  grid-template-columns: 1fr 1fr;
}

.paper-card h3 {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 600;
}

.paper-card p {
  margin: 6px 0 0;
  font-size: 11px;
  color: #6f675e;
}

.paper[data-per="1"] .ink-cell {
  font-size: clamp(18px, 4.2vw, 32px);
}

.paper.answers .paper-brand em {
  color: #1a1714;
}

.studio-note {
  color: var(--muted);
  margin: 0 0 18px;
}

.solver-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 56px;
  align-items: start;
}

.solver-board-wrap {
  width: var(--board);
}

.solver-status {
  min-height: 1.4em;
  color: var(--muted);
  margin: 0 0 12px;
  max-width: var(--board);
}

.solver-status.is-ok {
  color: var(--ok);
}

.solver-status.is-bad {
  color: var(--error);
}

.step-log {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  display: grid;
  gap: 8px;
  max-height: 420px;
  overflow: auto;
}

.step-log li {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 10px 12px;
}

.step-log b {
  display: block;
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-ink);
  margin-bottom: 2px;
}

.step-log span {
  color: var(--muted);
  font-size: 14px;
}

.paste {
  width: 100%;
  min-height: 74px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface);
  color: inherit;
  padding: 10px 12px;
  resize: vertical;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 12px;
  line-height: 1.4;
}

.guide {
  max-width: 720px;
}

.guide h2 {
  font-family: var(--font-display);
  font-size: 28px;
  margin: 36px 0 8px;
}

.guide h3 {
  font-family: var(--font-display);
  font-size: 22px;
  margin: 28px 0 8px;
}

.guide p,
.guide li {
  color: color-mix(in srgb, var(--ink) 78%, var(--muted));
}

.tech-grid {
  display: grid;
  gap: 12px;
  margin: 16px 0 8px;
}

.tech {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 18px;
}

.tech h3 {
  margin: 0 0 6px;
}

.tech p {
  margin: 0;
}

@media (max-width: 920px) {
  .solver-layout {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .paper {
    padding: 12px;
    min-height: 0;
  }
}