/* Project-local design tokens -- self-contained, no import from the main site
   (per web-projects/AGENTS.md). */
:root {
  --bg-1: #0f1523;
  --bg-2: #161f33;
  --panel: #1b2436;
  --panel-2: #212c42;
  --border: #2c3852;
  --text: #e8edf6;
  --text-muted: #9aa8c2;
  --accent: #5eb0ef;
  --accent-2: #7ee0c2;
  --warn: #f0c05a;
  --error: #f08a8a;
  --focus: #7ee0c2;
  --support: #f0c05a;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  --transition: 160ms ease;
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: radial-gradient(1200px 600px at 50% -10%, var(--bg-2), var(--bg-1)) fixed;
  min-height: 100vh;
  line-height: 1.55;
  padding: clamp(1rem, 4vw, 3rem) 1rem 3rem;
}

main {
  max-width: 900px;
  margin: 0 auto;
  display: grid;
  gap: 1.25rem;
}

.page-header {
  max-width: 900px;
  margin: 0 auto 1.75rem;
  text-align: center;
}

.page-header h1 {
  font-size: clamp(1.7rem, 4.5vw, 2.5rem);
  letter-spacing: -0.02em;
}

.subtitle {
  color: var(--text-muted);
  margin-top: 0.5rem;
  max-width: 46rem;
  margin-inline: auto;
}

.page-footer {
  max-width: 900px;
  margin: 2rem auto 0;
  color: var(--text-muted);
  font-size: 0.85rem;
  text-align: center;
}

/* --- panels --- */

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: clamp(1rem, 3vw, 1.5rem);
  box-shadow: var(--shadow);
}

.panel-title {
  font-size: 1.05rem;
  letter-spacing: 0.01em;
  margin-bottom: 0.75rem;
}

.panel-note {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-bottom: 1rem;
}

.row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  align-items: center;
  margin-top: 0.9rem;
}

kbd {
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0 0.3em;
  font-size: 0.85em;
  font-family: inherit;
}

/* --- drop zone --- */

.dropzone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: clamp(1.25rem, 5vw, 2.5rem) 1rem;
  text-align: center;
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition);
  background: rgba(255, 255, 255, 0.015);
}

.dropzone:hover,
.dropzone:focus-visible,
.dropzone.is-over {
  border-color: var(--accent);
  background: rgba(94, 176, 239, 0.07);
  outline: none;
}

.dropzone-icon {
  width: 34px;
  height: 34px;
  color: var(--accent);
  margin-bottom: 0.4rem;
}

.dropzone-title {
  font-weight: 600;
}

.dropzone-hint {
  color: var(--text-muted);
  font-size: 0.85rem;
  margin-top: 0.35rem;
}

/* --- buttons --- */

.ghost-button,
.mode-button {
  font: inherit;
  color: var(--text);
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.5rem 0.9rem;
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition), color var(--transition);
}

.ghost-button:hover,
.mode-button:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.ghost-button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.primary-button {
  font: inherit;
  font-weight: 600;
  color: #0d1420;
  background: var(--accent-2);
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  padding: 0.55rem 1rem;
  cursor: pointer;
  transition: filter var(--transition);
}

.primary-button:hover {
  filter: brightness(1.08);
}

.mode-switch {
  display: inline-flex;
  gap: 0.4rem;
  padding: 0.25rem;
  background: var(--bg-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  margin-bottom: 1rem;
}

.mode-button.is-active {
  background: var(--accent);
  border-color: var(--accent);
  color: #0d1420;
  font-weight: 600;
}

.toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-muted);
  font-size: 0.9rem;
  cursor: pointer;
}

/* --- status lines --- */

.status {
  margin-top: 0.9rem;
  font-size: 0.92rem;
  color: var(--text-muted);
  min-height: 1.4em;
}

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

.status.is-good {
  color: var(--accent-2);
}

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

.share-status {
  color: var(--accent-2);
  font-size: 0.85rem;
}

/* --- reader previews --- */

.reader-details {
  margin-top: 1rem;
  border-top: 1px solid var(--border);
  padding-top: 0.75rem;
}

.reader-details summary {
  cursor: pointer;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.reader-previews {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin-top: 0.9rem;
}

.reader-previews figcaption {
  color: var(--text-muted);
  font-size: 0.8rem;
  margin-top: 0.4rem;
}

.preview-canvas {
  width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: #0b0f18;
  image-rendering: auto;
}

/* --- the board --- */

.board-wrap {
  display: flex;
  justify-content: center;
}

.board {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  width: min(100%, 27rem);
  aspect-ratio: 1;
  background: var(--border);
  border: 3px solid var(--text-muted);
  border-radius: 6px;
  overflow: hidden;
  gap: 1px;
}

.cell {
  position: relative;
  font: inherit;
  color: var(--text);
  background: var(--bg-2);
  border: 0;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: clamp(1rem, 3.4vw, 1.45rem);
  font-variant-numeric: tabular-nums;
  transition: background var(--transition);
  padding: 0;
}

/* Thicker rules on the box borders, drawn as insets so the grid keeps its gaps. */
.cell[data-col="2"],
.cell[data-col="5"] {
  box-shadow: inset -2px 0 0 var(--text-muted);
}

.cell[data-row="2"],
.cell[data-row="5"] {
  box-shadow: inset 0 -2px 0 var(--text-muted);
}

.cell[data-col="2"][data-row="2"],
.cell[data-col="2"][data-row="5"],
.cell[data-col="5"][data-row="2"],
.cell[data-col="5"][data-row="5"] {
  box-shadow: inset -2px 0 0 var(--text-muted), inset 0 -2px 0 var(--text-muted);
}

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

.cell.is-derived {
  color: var(--accent);
  font-weight: 600;
}

.cell:hover {
  background: #223050;
}

.cell.is-selected {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
  z-index: 2;
}

.cell.is-house {
  background: #1d2a44;
}

.cell.is-support {
  background: #3a3520;
  color: var(--support);
}

.cell.is-focus {
  background: #1f4438;
  color: var(--focus);
  font-weight: 700;
}

.cell.is-uncertain::after {
  content: "";
  position: absolute;
  inset: auto 3px 3px auto;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--warn);
}

.cell.is-conflict {
  background: #4a2230;
  color: var(--error);
}

.cell .candidates {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  width: 100%;
  height: 100%;
  font-size: clamp(0.4rem, 1.25vw, 0.55rem);
  color: var(--text-muted);
  line-height: 1;
  align-items: center;
  justify-items: center;
  padding: 2px;
}

.cell .candidates span.is-move {
  color: var(--focus);
  font-weight: 700;
}

.cell .candidates span.is-cut {
  color: var(--error);
  text-decoration: line-through;
}

/* --- the coaching output --- */

.coach-output {
  display: grid;
  gap: 1rem;
}

.move-card {
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent-2);
  border-radius: var(--radius-sm);
  padding: 1rem;
}

.move-head {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: baseline;
  justify-content: space-between;
}

.move-title {
  font-size: 1.15rem;
  font-weight: 700;
}

.badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  padding: 0.15rem 0.55rem;
  border-radius: 999px;
  background: rgba(94, 176, 239, 0.15);
  color: var(--accent);
  border: 1px solid rgba(94, 176, 239, 0.35);
  white-space: nowrap;
}

.badge.is-difficulty {
  background: rgba(126, 224, 194, 0.13);
  color: var(--accent-2);
  border-color: rgba(126, 224, 194, 0.3);
}

.move-action {
  margin-top: 0.6rem;
  font-weight: 600;
  color: var(--accent-2);
}

.reason-heading {
  margin-top: 1rem;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.reason-list {
  margin: 0.4rem 0 0;
  padding-left: 1.1rem;
  display: grid;
  gap: 0.35rem;
}

.reason-list li::marker {
  color: var(--accent);
}

.technique-note {
  margin-top: 1rem;
  padding: 0.75rem 0.9rem;
  background: rgba(255, 255, 255, 0.03);
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  color: var(--text-muted);
}

.technique-note strong {
  color: var(--text);
}

.unlocks {
  margin-top: 0.9rem;
  font-size: 0.9rem;
  color: var(--text-muted);
  border-top: 1px dashed var(--border);
  padding-top: 0.7rem;
}

.step-list {
  display: grid;
  gap: 0.35rem;
  margin-top: 0.9rem;
  max-height: 22rem;
  overflow-y: auto;
  padding-right: 0.4rem;
}

.step {
  display: grid;
  grid-template-columns: 2.2rem 1fr;
  gap: 0.6rem;
  padding: 0.45rem 0.55rem;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.025);
  font-size: 0.88rem;
  cursor: pointer;
  border: 1px solid transparent;
  text-align: left;
  color: inherit;
  font-family: inherit;
}

.step:hover,
.step.is-active {
  border-color: var(--accent);
}

.step-index {
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}

.step-technique {
  color: var(--accent);
}

.summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 0.75rem;
  margin-top: 0.9rem;
}

.summary-item {
  background: rgba(255, 255, 255, 0.03);
  border-radius: var(--radius-sm);
  padding: 0.7rem 0.8rem;
}

.summary-item dt {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

.summary-item dd {
  margin-top: 0.2rem;
  font-weight: 600;
}

.notice {
  border-radius: var(--radius-sm);
  padding: 0.8rem 0.9rem;
  font-size: 0.92rem;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.03);
}

.notice.is-error {
  border-color: rgba(240, 138, 138, 0.4);
  color: var(--error);
  background: rgba(240, 138, 138, 0.08);
}

.notice.is-warn {
  border-color: rgba(240, 192, 90, 0.4);
  color: var(--warn);
  background: rgba(240, 192, 90, 0.07);
}

.notice.is-good {
  border-color: rgba(126, 224, 194, 0.4);
  color: var(--accent-2);
  background: rgba(126, 224, 194, 0.07);
}

/* --- glossary --- */

.glossary {
  display: grid;
  gap: 0.5rem;
}

.glossary-item {
  background: rgba(255, 255, 255, 0.025);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.6rem 0.8rem;
}

.glossary-item summary {
  cursor: pointer;
  font-weight: 600;
  display: flex;
  gap: 0.5rem;
  align-items: center;
  flex-wrap: wrap;
}

.glossary-item summary::marker {
  color: var(--accent);
}

.glossary-summary-text {
  font-weight: 400;
  color: var(--text-muted);
  font-size: 0.88rem;
}

.glossary-body {
  margin-top: 0.5rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

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

@media (prefers-reduced-motion: reduce) {
  * {
    transition: none !important;
  }
}

/* --- language picker --- */

.language-row {
  display: flex;
  justify-content: flex-end;
  margin-bottom: 0.5rem;
}

.language-picker select {
  font: inherit;
  font-size: 0.85rem;
  color: var(--text);
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.3rem 0.55rem;
  cursor: pointer;
}

.language-picker select:hover {
  border-color: var(--accent);
}

/* --- digit pad --- */

.digit-pad {
  display: grid;
  grid-template-columns: repeat(10, 1fr);
  gap: 0.35rem;
  width: min(100%, 27rem);
  margin: 0.75rem auto 0;
}

.pad-button {
  font: inherit;
  font-size: clamp(0.95rem, 3.2vw, 1.15rem);
  font-variant-numeric: tabular-nums;
  color: var(--text);
  background: var(--panel-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.55rem 0;
  cursor: pointer;
  transition: border-color var(--transition), color var(--transition);
  touch-action: manipulation;
}

.pad-button:hover,
.pad-button:focus-visible {
  border-color: var(--accent);
  color: var(--accent);
}

.pad-button.is-erase {
  color: var(--text-muted);
}

@media (max-width: 30rem) {
  .digit-pad {
    grid-template-columns: repeat(5, 1fr);
  }

  .mode-switch {
    display: grid;
    grid-template-columns: 1fr 1fr;
    width: 100%;
  }

  .summary-grid {
    grid-template-columns: 1fr;
  }
}