:root {
  color-scheme: dark;
  --bg: #111310;
  --surface: #181b17;
  --surface-raised: #20241e;
  --surface-hover: #292e27;
  --line: #343a31;
  --line-strong: #4a5245;
  --text: #f2f3ee;
  --muted: #aeb5a9;
  --subtle: #7e8779;
  --accent: #d4ed67;
  --accent-ink: #172000;
  --hill: #dfb748;
  --danger: #ef7e67;
  --light-square: #d9d8cb;
  --dark-square: #64705d;
  --board-size: min(68vh, 100%);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-synthesis: none;
}

* {
  box-sizing: border-box;
}

html,
body {
  min-height: 100%;
  margin: 0;
}

body {
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.45;
}

button,
input,
textarea {
  font: inherit;
}

button {
  color: inherit;
}

button:focus-visible,
input:focus-visible,
textarea:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.app-header {
  align-items: center;
  background: #151714;
  border-bottom: 1px solid var(--line);
  display: flex;
  height: 68px;
  justify-content: space-between;
  padding: 0 22px;
}

.brand {
  align-items: center;
  color: var(--text);
  display: inline-flex;
  gap: 11px;
  text-decoration: none;
}

.brand-mark {
  align-items: center;
  background: var(--accent);
  border-radius: 4px;
  color: var(--accent-ink);
  display: flex;
  font-family: Georgia, serif;
  font-size: 24px;
  font-weight: 800;
  height: 38px;
  justify-content: center;
  width: 38px;
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  font-size: 17px;
  line-height: 1.1;
}

.brand small {
  color: var(--muted);
  font-size: 12px;
  margin-top: 3px;
}

.header-actions,
.engine-status {
  align-items: center;
  display: flex;
}

.header-actions {
  gap: 12px;
}

.saved-open,
.library-close,
.library-backdrop {
  display: none;
}

.engine-status {
  color: var(--muted);
  font-size: 13px;
  gap: 7px;
}

.status-dot {
  background: var(--subtle);
  border-radius: 50%;
  height: 8px;
  width: 8px;
}

.engine-status[data-state="ready"] .status-dot {
  background: var(--accent);
  box-shadow: 0 0 0 3px rgb(212 237 103 / 12%);
}

.engine-status[data-state="working"] .status-dot {
  animation: pulse 1s infinite alternate;
  background: var(--hill);
}

.engine-status[data-state="error"] .status-dot {
  background: var(--danger);
}

@keyframes pulse {
  to { opacity: 0.35; }
}

.workspace {
  display: grid;
  grid-template-columns: 250px minmax(420px, 1fr) 340px;
  min-height: calc(100vh - 68px);
}

.library-panel,
.analysis-panel {
  background: var(--surface);
  min-width: 0;
  padding: 20px;
}

.library-panel {
  border-right: 1px solid var(--line);
  display: flex;
  flex-direction: column;
}

.analysis-panel {
  border-left: 1px solid var(--line);
}

.panel-heading,
.game-heading,
.dialog-heading {
  align-items: flex-start;
  display: flex;
  justify-content: space-between;
}

.eyebrow {
  color: var(--subtle);
  font-size: 11px;
  font-weight: 750;
  letter-spacing: 0;
  margin: 0 0 4px;
  text-transform: uppercase;
}

h1,
h2,
p {
  margin-top: 0;
}

h1 {
  font-size: clamp(21px, 2.3vw, 30px);
  line-height: 1.15;
  margin-bottom: 5px;
}

h2 {
  font-size: 18px;
  line-height: 1.2;
  margin-bottom: 0;
}

.count-badge {
  align-items: center;
  background: var(--surface-raised);
  border: 1px solid var(--line);
  border-radius: 4px;
  color: var(--muted);
  display: flex;
  font-size: 12px;
  font-weight: 700;
  height: 26px;
  justify-content: center;
  min-width: 26px;
}

.panel-heading-actions {
  align-items: center;
  display: flex;
  gap: 8px;
}

.library-list {
  display: grid;
  gap: 6px;
  margin: 18px -8px 14px;
  max-height: calc(100vh - 220px);
  overflow-y: auto;
  padding: 0 8px;
}

.library-game {
  background: transparent;
  border: 1px solid transparent;
  border-radius: 6px;
  cursor: pointer;
  padding: 10px;
  text-align: left;
  width: 100%;
}

.library-entry {
  position: relative;
}

.library-entry .library-game {
  padding-right: 34px;
}

.library-remove {
  align-items: center;
  background: transparent;
  border: 0;
  border-radius: 3px;
  color: var(--subtle);
  cursor: pointer;
  display: flex;
  font-size: 18px;
  height: 28px;
  justify-content: center;
  position: absolute;
  right: 6px;
  top: 7px;
  width: 28px;
}

.library-remove:hover {
  background: rgb(239 126 103 / 12%);
  color: var(--danger);
}

.library-game:hover,
.library-game.active {
  background: var(--surface-raised);
  border-color: var(--line);
}

.library-game strong,
.library-game span {
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.library-game strong {
  font-size: 14px;
}

.library-game span {
  color: var(--muted);
  font-size: 12px;
  margin-top: 4px;
}

.library-game time {
  color: var(--subtle);
  display: block;
  font-size: 11px;
  margin-top: 7px;
}

.empty-library {
  color: var(--muted);
  margin: auto 0;
  padding: 28px 8px;
  text-align: center;
}

.empty-library[hidden] {
  display: none;
}

.empty-library p {
  color: var(--text);
  font-weight: 650;
  margin: 8px 0 2px;
}

.empty-library small {
  color: var(--subtle);
}

.empty-icon {
  color: var(--line-strong);
  font-size: 34px;
}

.button,
.icon-button,
.text-button,
.tab {
  border: 0;
  cursor: pointer;
}

.button {
  border-radius: 5px;
  font-weight: 720;
  min-height: 40px;
  padding: 9px 14px;
}

.button.primary {
  background: var(--accent);
  color: var(--accent-ink);
}

.button.primary:hover {
  background: #e1f58a;
}

.button.secondary {
  background: var(--surface-raised);
  border: 1px solid var(--line-strong);
}

.button.secondary:hover {
  background: var(--surface-hover);
}

.button.compact {
  min-height: 36px;
  padding: 7px 11px;
}

.button:disabled,
.icon-button:disabled {
  cursor: not-allowed;
  opacity: 0.42;
}

.full-width {
  width: 100%;
}

.board-section {
  align-items: center;
  display: flex;
  flex-direction: column;
  min-width: 0;
  padding: 24px clamp(20px, 3vw, 48px) 26px;
}

.game-heading,
.board-eval-layout,
.board-toolbar,
.hill-rule {
  max-width: 760px;
  width: 100%;
}

.game-heading {
  align-items: center;
  margin-bottom: 14px;
}

.player-line {
  color: var(--muted);
  margin: 0;
}

.player-line span {
  color: var(--subtle);
  margin: 0 5px;
}

.icon-button {
  align-items: center;
  background: var(--surface-raised);
  border: 1px solid var(--line);
  border-radius: 4px;
  display: inline-flex;
  font-size: 20px;
  height: 38px;
  justify-content: center;
  min-width: 38px;
  padding: 0 8px;
}

.icon-button:hover {
  background: var(--surface-hover);
}

.icon-button.library-close {
  display: none;
}

.board-eval-layout {
  display: grid;
  grid-template-columns: 18px minmax(0, 1fr);
  gap: 9px;
  width: min(100%, calc(70vh + 27px));
}

.board-wrap {
  aspect-ratio: 1;
  background: #0a0b09;
  border: 1px solid var(--line-strong);
  box-shadow: 0 12px 36px rgb(0 0 0 / 28%);
  width: 100%;
}

.board {
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
  height: 100%;
  position: relative;
  width: 100%;
}

.analysis-arrows {
  height: 100%;
  inset: 0;
  overflow: visible;
  pointer-events: none;
  position: absolute;
  width: 100%;
  z-index: 4;
}

.square {
  align-items: center;
  display: flex;
  justify-content: center;
  position: relative;
  user-select: none;
}

.square.playable {
  cursor: grab;
}

.square.playable:active {
  cursor: grabbing;
}

.square.selected {
  outline: 4px solid rgb(212 237 103 / 75%);
  outline-offset: -4px;
}

.square.legal-target::before,
.square.legal-capture::before {
  border-radius: 50%;
  content: "";
  pointer-events: none;
  position: absolute;
  z-index: 3;
}

.square.legal-target::before {
  background: rgb(32 36 30 / 35%);
  height: 24%;
  width: 24%;
}

.square.legal-capture::before {
  border: max(4px, 0.55vw) solid rgb(32 36 30 / 38%);
  inset: 7%;
}

.square.light {
  background: var(--light-square);
}

.square.dark {
  background: var(--dark-square);
}

.square.hill::after {
  border: max(3px, 0.45vw) solid rgb(223 183 72 / 80%);
  content: "";
  inset: 8%;
  pointer-events: none;
  position: absolute;
}

.square.last-move {
  box-shadow: inset 0 0 0 999px rgb(212 237 103 / 27%);
}

.square.check {
  box-shadow: inset 0 0 0 999px rgb(239 126 103 / 42%);
}

.square.hill-winner {
  box-shadow: inset 0 0 0 999px rgb(212 237 103 / 38%);
}

.piece {
  height: 92%;
  object-fit: contain;
  position: relative;
  user-select: none;
  width: 92%;
  z-index: 1;
}

.square.playable .piece {
  cursor: grab;
}

.square.playable .piece:active {
  cursor: grabbing;
}

.coord {
  font-size: clamp(9px, 1vw, 12px);
  font-weight: 800;
  opacity: 0.7;
  position: absolute;
  z-index: 2;
}

.coord.file {
  bottom: 2px;
  right: 4px;
}

.coord.rank {
  left: 4px;
  top: 2px;
}

.light .coord { color: var(--dark-square); }
.dark .coord { color: var(--light-square); }

.evaluation-bar {
  background: #141613;
  border: 1px solid var(--line-strong);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  position: relative;
}

.eval-black,
.eval-white {
  transition: height 360ms ease;
  width: 100%;
}

.eval-black {
  background: #252824;
  height: 50%;
}

.eval-white {
  background: #ebeee5;
  height: 50%;
}

.eval-label {
  background: #111310;
  border-radius: 3px;
  font-size: 10px;
  font-weight: 750;
  left: 50%;
  padding: 2px 3px;
  position: absolute;
  top: 50%;
  transform: translate(-50%, -50%) rotate(-90deg);
}

.board-toolbar {
  align-items: center;
  display: grid;
  gap: 7px;
  grid-template-columns: 38px 38px 1fr 38px 38px;
  margin-top: 12px;
}

.position-label {
  color: var(--muted);
  font-size: 13px;
  text-align: center;
}

.position-status {
  align-items: center;
  display: flex;
  flex-wrap: wrap;
  gap: 2px 8px;
  justify-content: center;
  min-width: 0;
}

.return-preview {
  font-size: 12px;
  padding: 2px 4px;
}

.hill-rule {
  align-items: center;
  border-top: 1px solid var(--line);
  display: flex;
  gap: 10px;
  margin-top: 16px;
  padding-top: 14px;
}

.hill-rule p {
  color: var(--muted);
  font-size: 13px;
  margin: 0;
}

.hill-rule strong {
  color: var(--text);
}

.hill-swatch {
  border: 3px solid var(--hill);
  flex: 0 0 auto;
  height: 21px;
  width: 21px;
}

.analysis-tabs {
  border-bottom: 1px solid var(--line);
  display: flex;
  margin: -4px 0 20px;
}

.tab {
  background: transparent;
  border-bottom: 2px solid transparent;
  color: var(--muted);
  font-weight: 700;
  padding: 11px 14px;
}

.tab.active {
  border-bottom-color: var(--accent);
  color: var(--text);
}

.engine-summary {
  align-items: flex-start;
  display: flex;
  justify-content: space-between;
}

.score {
  display: block;
  font-size: 34px;
  line-height: 1;
  margin: 5px 0 5px;
}

.engine-summary span {
  color: var(--muted);
  font-size: 13px;
}

.engine-controls {
  width: 142px;
}

.depth-control label {
  color: var(--muted);
  display: flex;
  font-size: 12px;
  justify-content: space-between;
}

input[type="range"] {
  accent-color: var(--accent);
  margin-top: 8px;
  width: 100%;
}

.arrow-control {
  border-top: 1px solid var(--line);
  margin-top: 12px;
  padding-top: 10px;
}

.toggle-label {
  align-items: center;
  color: var(--muted);
  cursor: pointer;
  display: flex;
  font-size: 12px;
  gap: 7px;
}

.toggle-label input {
  accent-color: var(--accent);
  height: 15px;
  margin: 0;
  width: 15px;
}

.toggle-label span {
  font-size: 12px;
}

.line-selector {
  display: grid;
  gap: 4px;
  grid-template-columns: repeat(3, 1fr);
  margin-top: 8px;
}

.line-choice {
  background: var(--surface-raised);
  border: 1px solid var(--line-strong);
  border-radius: 3px;
  color: var(--muted);
  cursor: pointer;
  font-size: 12px;
  font-weight: 750;
  height: 27px;
  padding: 0;
}

.line-choice:hover {
  background: var(--surface-hover);
}

.line-choice.active {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-ink);
}

.line-choice:disabled,
.toggle-label:has(input:disabled) {
  cursor: not-allowed;
  opacity: 0.5;
}

.principal-variation {
  border-bottom: 1px solid var(--line);
  border-top: 1px solid var(--line);
  margin-top: 22px;
  min-height: 128px;
  padding: 17px 0;
}

.principal-variation ol {
  display: grid;
  gap: 10px;
  list-style: none;
  margin: 12px 0 0;
  padding: 0;
}

.principal-variation li {
  font-size: 13px;
}

.pv-line-row {
  align-items: start;
  display: grid;
  gap: 7px;
  grid-template-columns: 50px minmax(0, 1fr);
}

.pv-line-meta {
  color: var(--subtle);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 11px;
  padding-top: 5px;
  white-space: nowrap;
}

.pv-line-moves {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}

.pv-move {
  background: var(--surface-raised);
  border: 0;
  border-radius: 3px;
  color: var(--text);
  cursor: pointer;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 12px;
  padding: 4px 6px;
}

.pv-move:hover {
  background: var(--surface-hover);
}

.pv-move.active {
  background: var(--accent);
  color: var(--accent-ink);
}

.principal-variation li.muted {
  background: transparent;
  color: var(--subtle);
  font-family: inherit;
  padding-left: 0;
}

.analysis-actions {
  display: grid;
  gap: 8px;
  grid-template-columns: 1fr 1fr;
  margin-top: 18px;
}

.progress-wrap {
  align-items: center;
  display: grid;
  gap: 8px;
  grid-template-columns: 1fr auto;
  margin-top: 14px;
}

.progress-wrap[hidden] { display: none; }

.progress-track {
  background: var(--line);
  grid-column: 1 / -1;
  height: 5px;
  overflow: hidden;
}

.progress-track span {
  background: var(--accent);
  display: block;
  height: 100%;
  transition: width 180ms ease;
  width: 0;
}

#progress-text {
  color: var(--muted);
  font-size: 12px;
}

.text-button {
  background: transparent;
  color: var(--accent);
  font-size: 13px;
  font-weight: 700;
  padding: 4px;
}

.text-button:hover { color: #e6fa8e; }

.position-facts {
  border-top: 1px solid var(--line);
  display: grid;
  gap: 0;
  margin-top: 20px;
}

.position-facts div {
  align-items: center;
  border-bottom: 1px solid var(--line);
  display: flex;
  justify-content: space-between;
  padding: 11px 0;
}

.position-facts span {
  color: var(--muted);
  font-size: 13px;
}

.position-facts strong {
  font-size: 13px;
}

.engine-note {
  background: #22251f;
  border-left: 3px solid var(--hill);
  color: var(--muted);
  font-size: 12px;
  margin-top: 18px;
  padding: 10px 11px;
}

.move-list {
  display: grid;
  grid-template-columns: 42px 1fr 1fr;
  max-height: calc(100vh - 190px);
  overflow-y: auto;
}

.move-number,
.move-button {
  border-bottom: 1px solid var(--line);
  min-height: 38px;
  padding: 8px;
}

.move-number {
  color: var(--subtle);
  font-size: 12px;
}

.move-button {
  background: transparent;
  border-left: 0;
  border-right: 0;
  border-top: 0;
  cursor: pointer;
  text-align: left;
}

.move-button:hover,
.move-button.active {
  background: var(--surface-hover);
}

.move-button .move-eval {
  color: var(--subtle);
  float: right;
  font-size: 11px;
}

.empty-moves {
  color: var(--subtle);
  padding: 40px 10px;
  text-align: center;
}

.save-strip {
  align-items: center;
  border-top: 1px solid var(--line);
  bottom: 0;
  display: flex;
  justify-content: space-between;
  margin: 24px -20px -20px;
  padding: 14px 20px;
}

.save-strip span {
  color: var(--subtle);
  font-size: 12px;
}

.import-dialog {
  background: transparent;
  border: 0;
  color: var(--text);
  max-width: 680px;
  padding: 18px;
  width: calc(100% - 24px);
}

.import-dialog::backdrop {
  background: rgb(4 5 4 / 78%);
}

.dialog-shell {
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: 7px;
  box-shadow: 0 24px 70px rgb(0 0 0 / 55%);
  padding: 22px;
}

.dialog-heading {
  margin-bottom: 20px;
}

.dialog-shell > label {
  display: block;
  font-size: 13px;
  font-weight: 700;
  margin-bottom: 7px;
}

textarea {
  background: #10120f;
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  color: var(--text);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 13px;
  line-height: 1.55;
  padding: 12px;
  resize: vertical;
  width: 100%;
}

.form-error {
  color: var(--danger);
  font-size: 13px;
  min-height: 20px;
  margin: 6px 0 0;
}

.dialog-actions {
  align-items: center;
  display: flex;
  gap: 8px;
  margin-top: 12px;
}

.dialog-spacer { flex: 1; }

.toast {
  background: var(--text);
  border-radius: 5px;
  bottom: 20px;
  color: #171916;
  font-size: 13px;
  font-weight: 700;
  left: 50%;
  opacity: 0;
  padding: 10px 14px;
  pointer-events: none;
  position: fixed;
  transform: translate(-50%, 12px);
  transition: opacity 180ms ease, transform 180ms ease;
  z-index: 20;
}

.toast.visible {
  opacity: 1;
  transform: translate(-50%, 0);
}

@media (max-width: 1180px) {
  .workspace {
    grid-template-columns: minmax(400px, 1fr) 320px;
  }

  .library-panel {
    bottom: 0;
    box-shadow: 20px 0 55px rgb(0 0 0 / 45%);
    display: flex;
    left: 0;
    max-width: calc(100vw - 42px);
    position: fixed;
    top: 0;
    transform: translateX(-105%);
    transition: transform 180ms ease;
    width: 300px;
    z-index: 12;
  }

  .library-panel.open {
    transform: translateX(0);
  }

  .saved-open,
  .icon-button.library-close {
    display: inline-flex;
  }

  .library-close {
    height: 30px;
    min-width: 30px;
  }

  .library-backdrop {
    background: rgb(0 0 0 / 58%);
    border: 0;
    bottom: 0;
    cursor: pointer;
    left: 0;
    position: fixed;
    right: 0;
    top: 0;
    z-index: 11;
  }

  .library-backdrop.visible {
    display: block;
  }

  .board-section {
    padding-left: 24px;
    padding-right: 24px;
  }
}

@media (max-width: 790px) {
  .app-header {
    height: 60px;
    padding: 0 12px;
  }

  .brand small,
  .engine-status span:last-child {
    display: none;
  }

  .workspace {
    display: block;
    min-height: calc(100vh - 60px);
  }

  .board-section {
    padding: 18px 12px 20px;
  }

  .analysis-panel {
    border-left: 0;
    border-top: 1px solid var(--line);
    padding: 20px 14px;
  }

  .save-strip {
    margin-left: -14px;
    margin-right: -14px;
  }

  .board-wrap {
    max-height: none;
  }

  .hill-rule {
    align-items: flex-start;
  }

  .move-list {
    max-height: 480px;
  }
}

@media (max-width: 430px) {
  .header-actions .button:not(.saved-open) {
    font-size: 0;
    min-width: 38px;
    padding: 7px;
  }

  .header-actions .button:not(.saved-open) span {
    font-size: 20px;
  }

  .saved-open {
    font-size: 12px;
    min-width: auto;
    padding-left: 9px;
    padding-right: 9px;
  }

  .game-heading {
    align-items: flex-start;
  }

  .board-section h1 {
    max-width: 270px;
  }

  .analysis-actions {
    grid-template-columns: 1fr;
  }

  .engine-summary {
    gap: 16px;
  }

  .dialog-actions {
    flex-wrap: wrap;
  }

  .dialog-spacer { display: none; }

  .dialog-actions .button {
    flex: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
  }
}