:root {
  --bg-deep: #120c07;
  --bg-mid: #191209;
  --panel: #251a10;
  --panel-2: #2d2013;
  --edge: #3f2e1b;
  --edge-soft: rgba(216, 180, 95, 0.22);
  --gold: #d8b45f;
  --gold-bright: #f2d488;
  --gold-dim: #a8873f;
  --cream: #f4ead4;
  --muted: #bda887;
  --ink-dark: #241708;
  --danger: #e0604a;
  --sq-light-a: #d1a26b;
  --sq-light-b: #c08e52;
  --sq-dark-a: #74502c;
  --sq-dark-b: #61401f;
  --board-radius: 14px;
  --rail-w: 352px;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  overflow-x: hidden;
}

html {
  background: var(--bg-deep);
}

body {
  min-height: 100vh;
  color: var(--cream);
  font-family: "Segoe UI", "Microsoft JhengHei", "PingFang TC", "Noto Sans TC", system-ui, sans-serif;
  background:
    radial-gradient(1100px 700px at 82% -12%, rgba(216, 180, 95, 0.13), transparent 60%),
    radial-gradient(900px 650px at -15% 110%, rgba(120, 72, 28, 0.22), transparent 55%),
    linear-gradient(180deg, var(--bg-mid), var(--bg-deep) 85%);
  background-attachment: fixed;
  display: flex;
  flex-direction: column;
}

body.modal-open {
  overflow: hidden;
}

.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;
}

.noscript-note {
  margin: 0;
  padding: 12px 16px;
  text-align: center;
  background: var(--danger);
  color: #fff;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 100;
  padding: 10px 16px;
  background: var(--gold);
  color: var(--ink-dark);
  border-radius: 0 0 8px 0;
  font-weight: 700;
}

.skip-link:focus {
  left: 0;
}

.site-header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  max-width: 1180px;
  width: 100%;
  margin: 0 auto;
  padding: 26px 24px 14px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-mark {
  width: 54px;
  height: 54px;
  display: grid;
  place-items: center;
  font-size: 34px;
  line-height: 1;
  color: var(--gold-bright);
  background: linear-gradient(160deg, #33230f, #1d130a);
  border: 1px solid var(--edge);
  border-radius: 12px;
  box-shadow:
    inset 0 0 0 1px rgba(242, 212, 136, 0.12),
    0 6px 18px rgba(0, 0, 0, 0.45);
}

.brand-title {
  margin: 0;
  font-family: "Palatino Linotype", Palatino, "Noto Serif TC", "Songti TC", serif;
  font-size: clamp(22px, 3.4vw, 32px);
  letter-spacing: 2px;
  color: var(--cream);
  text-shadow: 0 2px 12px rgba(216, 180, 95, 0.25);
}

.brand-badge {
  margin: 4px 0 0;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--gold);
}

.brand-badge::before {
  content: "";
  display: inline-block;
  width: 26px;
  height: 1px;
  margin-right: 10px;
  vertical-align: middle;
  background: linear-gradient(90deg, transparent, var(--gold));
}

.brand-tag {
  margin: 0 0 6px;
  font-size: 13px;
  letter-spacing: 6px;
  color: var(--muted);
}

.layout {
  flex: 1;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  gap: 28px;
  width: 100%;
  max-width: 1180px;
  margin: 0 auto;
  padding: 10px 24px 34px;
}

.board-zone {
  flex: 1 1 auto;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  min-width: 0;
}

.board-wrap {
  position: relative;
  width: var(--board-size);
  max-width: 100%;
}

.board-frame {
  --board-size: max(
    288px,
    min(608px, calc(100vw - 448px), calc(100vh - 236px))
  );
  --glyph-base: calc(var(--board-size) / 10.2);
  display: grid;
  grid-template-columns: 1.55rem var(--board-size);
  grid-template-rows: var(--board-size) 1.45rem;
  gap: 7px;
  padding: 14px;
  border-radius: var(--board-radius);
  background: linear-gradient(155deg, #38271442, #1c120866),
    linear-gradient(180deg, #2a1c0e, #201409);
  border: 1px solid var(--edge-soft);
  box-shadow:
    inset 0 0 0 1px rgba(0, 0, 0, 0.55),
    0 18px 48px rgba(0, 0, 0, 0.55),
    0 2px 0 rgba(242, 212, 136, 0.06);
}

@supports (height: 100dvh) {
  .board-frame {
    --board-size: max(
      288px,
      min(608px, calc(100vw - 448px), calc(100dvh - 236px))
    );
    --glyph-base: calc(var(--board-size) / 10.2);
  }
}

.coords {
  display: flex;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1px;
  user-select: none;
}

.coords-ranks {
  grid-column: 1;
  grid-row: 1;
  flex-direction: column;
  justify-content: space-around;
  align-items: center;
}

.coords-files {
  grid-column: 2;
  grid-row: 2;
  flex-direction: row;
  justify-content: space-around;
  align-items: center;
}

.board-grid {
  grid-column: 2;
  grid-row: 1;
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
  border-radius: 8px;
  overflow: hidden;
  outline: none;
}

.grid-row {
  display: contents;
}

.sq-cell {
  display: block;
  padding: 0;
}

button.sq {
  appearance: none;
  -webkit-appearance: none;
  display: grid;
  place-items: center;
  width: 100%;
  height: 100%;
  padding: 0;
  border: 0;
  position: relative;
  cursor: pointer;
  font: inherit;
  line-height: 1;
  transition: filter 0.12s ease;
}

button.sq.light {
  background: linear-gradient(135deg, var(--sq-light-a), var(--sq-light-b));
}

button.sq.dark {
  background: linear-gradient(135deg, var(--sq-dark-a), var(--sq-dark-b));
}

button.sq::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
}

button.sq.last-move::before {
  background: rgba(242, 212, 136, 0.28);
  box-shadow: inset 0 0 0 2px rgba(242, 212, 136, 0.35);
}

button.sq.selected {
  box-shadow: inset 0 0 0 3px var(--gold-bright);
  filter: brightness(1.12);
}

/* 提示建議著法的起／訖格：虛線金框，與選取、上一手與落點標記可並存 */
button.sq.hint-move {
  outline: 3px dashed var(--gold-bright);
  outline-offset: -4px;
}

button.sq.dest-quiet::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 27%;
  height: 27%;
  transform: translate(-50%, -50%);
  border-radius: 50%;
  background: radial-gradient(circle at 38% 32%, rgba(242, 212, 136, 0.95), rgba(170, 128, 52, 0.75));
  box-shadow: 0 0 8px rgba(242, 212, 136, 0.5);
}

button.sq.dest-capture::after {
  content: "";
  position: absolute;
  inset: 6%;
  border-radius: 50%;
  border: 3px solid rgba(224, 96, 74, 0.9);
  box-shadow:
    inset 0 0 10px rgba(224, 96, 74, 0.35),
    0 0 10px rgba(224, 96, 74, 0.35);
}

button.sq.in-check {
  animation: checkPulse 0.9s ease-in-out infinite alternate;
}

@keyframes checkPulse {
  from {
    box-shadow: inset 0 0 0 3px rgba(224, 96, 74, 0.65);
  }
  to {
    box-shadow:
      inset 0 0 0 4px rgba(224, 96, 74, 0.95),
      inset 0 0 22px rgba(224, 96, 74, 0.55);
  }
}

.piece-glyph {
  transform: translateY(-2%);
  user-select: none;
  pointer-events: none;
}

.board-frame .piece-glyph {
  font-size: var(--glyph-base, 56px);
}

.tray-pieces .piece-glyph {
  font-size: 22px;
  line-height: 1.15;
}

.piece-w {
  color: #faf3e1;
  text-shadow:
    0 1px 0 rgba(20, 12, 4, 0.9),
    0 0 3px rgba(20, 12, 4, 0.85),
    0 2px 5px rgba(0, 0, 0, 0.5);
}

.piece-b {
  color: #17100a;
  text-shadow:
    0 1px 0 rgba(242, 212, 136, 0.28),
    0 0 3px rgba(242, 212, 136, 0.22),
    0 2px 4px rgba(240, 220, 170, 0.28);
}

@media (hover: hover) {
  .board-grid:not(.locked) button.sq:hover {
    filter: brightness(1.09);
  }

  .board-grid:not(.locked) button.sq:has(.piece-glyph):hover .piece-glyph {
    transform: translateY(-2%) scale(1.05);
  }
}

button.sq:focus-visible {
  outline: 3px solid var(--gold-bright);
  outline-offset: -3px;
  z-index: 2;
}

.board-grid.locked button.sq {
  cursor: default;
}

.board-grid.locked {
  opacity: 0.92;
}

.banner-kicker {
  margin: 0;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 4px;
  color: var(--muted);
}

.rail {
  flex: 0 0 var(--rail-w);
  width: var(--rail-w);
  display: flex;
  flex-direction: column;
  gap: 16px;
  min-width: 0;
}

.panel {
  background: linear-gradient(175deg, var(--panel-2), var(--panel));
  border: 1px solid var(--edge);
  border-radius: 12px;
  box-shadow:
    inset 0 1px 0 rgba(242, 212, 136, 0.07),
    0 10px 26px rgba(0, 0, 0, 0.4);
  padding: 16px;
}

.panel-heading,
.tray-heading {
  margin: 0 0 10px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--gold);
}

.status-line {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.status-main {
  margin: 0;
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 1px;
  color: var(--cream);
}

.status-sub {
  margin: 7px 0 0;
  font-size: 13px;
  color: var(--muted);
  letter-spacing: 0.5px;
  min-height: 1.2em;
}

.thinking {
  display: inline-flex;
  align-items: flex-end;
  gap: 4px;
  height: 20px;
  flex: 0 0 auto;
}

.thinking i {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--gold-bright);
  animation: dotBounce 0.9s ease-in-out infinite;
}

.thinking i:nth-child(2) {
  animation-delay: 0.15s;
}

.thinking i:nth-child(3) {
  animation-delay: 0.3s;
}

@keyframes dotBounce {
  0%,
  100% {
    transform: translateY(0);
    opacity: 0.45;
  }
  50% {
    transform: translateY(-7px);
    opacity: 1;
  }
}

.hidden {
  display: none !important;
}

.mode-set {
  margin: 0 0 14px;
  padding: 0;
  border: 0;
}

.mode-set legend {
  padding: 0;
  margin-bottom: 8px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 3px;
  color: var(--gold);
}

.segment {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  border: 1px solid var(--edge);
  border-radius: 10px;
  overflow: hidden;
  background: #1b1209;
}

.segment input[type="radio"] {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.segment label {
  display: grid;
  place-items: center;
  min-height: 46px;
  padding: 8px 10px;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--muted);
  background: transparent;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease;
  user-select: none;
}

.segment label:nth-of-type(1) {
  border-right: 1px solid var(--edge);
}

.segment input[type="radio"]:checked + label {
  background: linear-gradient(180deg, var(--gold), #bd9440);
  color: var(--ink-dark);
  text-shadow: 0 1px 0 rgba(255, 240, 200, 0.4);
}

.segment input[type="radio"]:focus-visible + label {
  outline: 3px solid var(--gold-bright);
  outline-offset: -3px;
}

.level-row {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 14px;
}

.level-row label {
  flex: 0 0 auto;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 3px;
  color: var(--gold);
}

select#levelSelect {
  appearance: none;
  -webkit-appearance: none;
  flex: 1;
  min-height: 46px;
  padding: 8px 34px 8px 12px;
  font: inherit;
  font-size: 15px;
  color: var(--cream);
  background:
    linear-gradient(45deg, transparent 50%, var(--gold) 50%) calc(100% - 18px) 55% / 7px 7px no-repeat,
    linear-gradient(-45deg, transparent 50%, var(--gold) 50%) calc(100% - 12px) 55% / 7px 7px no-repeat,
    linear-gradient(180deg, #1b1209, #211609);
  border: 1px solid var(--edge);
  border-radius: 10px;
  cursor: pointer;
  color-scheme: dark;
}

select#levelSelect:focus-visible {
  outline: 3px solid var(--gold-bright);
  outline-offset: 1px;
}

.action-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

/* 宣告和棋僅在可主張時顯示，出現時佔滿整列，維持原有雙鍵布局 */
#claimDrawBtn:not(.hidden) {
  grid-column: 1 / -1;
}

.btn {
  appearance: none;
  -webkit-appearance: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 47px;
  padding: 10px 18px;
  font: inherit;
  font-size: 16px;
  font-weight: 700;
  letter-spacing: 3px;
  border-radius: 10px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 0.12s ease, filter 0.12s ease, box-shadow 0.12s ease;
  user-select: none;
}

.btn.primary {
  color: var(--ink-dark);
  background: linear-gradient(180deg, var(--gold-bright), var(--gold) 55%, #b98f3c);
  border-color: #8a6a2c;
  box-shadow:
    inset 0 1px 0 rgba(255, 245, 214, 0.55),
    0 6px 16px rgba(0, 0, 0, 0.45);
}

.btn.primary:hover:not(:disabled) {
  filter: brightness(1.07);
}

.btn.ghost {
  color: var(--gold-bright);
  background: rgba(242, 212, 136, 0.05);
  border-color: var(--edge-soft);
}

.btn.ghost:hover:not(:disabled) {
  background: rgba(242, 212, 136, 0.12);
}

.btn.danger {
  color: #fff;
  background: linear-gradient(180deg, #d96a52, #b64a35);
  border-color: #7e3323;
}

.btn.danger:hover {
  filter: brightness(1.08);
}

.btn:active:not(:disabled) {
  transform: translateY(1px);
}

.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.btn:focus-visible {
  outline: 3px solid var(--gold-bright);
  outline-offset: 2px;
}

.btn.block {
  width: 100%;
  margin-top: 14px;
}

.captured-panel {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.tray-heading {
  margin-bottom: 6px;
  display: flex;
  justify-content: space-between;
  align-items: baseline;
}

.tray-heading .lead {
  color: var(--gold-bright);
  font-size: 14px;
  letter-spacing: 1px;
}

.tray-pieces {
  min-height: 34px;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1px;
  padding: 4px 8px;
  border-radius: 8px;
  background: rgba(0, 0, 0, 0.28);
  border: 1px solid rgba(63, 46, 27, 0.8);
  font-size: 22px;
  line-height: 1.15;
}

.tray-empty {
  font-size: 12px;
  letter-spacing: 2px;
  color: rgba(189, 168, 135, 0.55);
}

.history-panel {
  display: flex;
  flex-direction: column;
  min-height: 150px;
}

.move-list {
  margin: 0;
  padding: 0;
  list-style: none;
  overflow-y: auto;
  max-height: 218px;
  scrollbar-width: thin;
  scrollbar-color: var(--gold-dim) rgba(0, 0, 0, 0.3);
  border: 1px solid rgba(63, 46, 27, 0.8);
  border-radius: 8px;
  background: rgba(0, 0, 0, 0.24);
}

.move-list::-webkit-scrollbar {
  width: 8px;
}

.move-list::-webkit-scrollbar-track {
  background: rgba(0, 0, 0, 0.3);
}

.move-list::-webkit-scrollbar-thumb {
  background: var(--gold-dim);
  border-radius: 4px;
}

.move-row {
  display: grid;
  grid-template-columns: 2.6em 1fr 1fr;
  align-items: baseline;
  padding: 6px 12px;
  font-size: 14px;
  letter-spacing: 0.5px;
}

.move-row:nth-child(odd) {
  background: rgba(255, 255, 255, 0.02);
}

.move-num {
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

.move-san {
  padding: 1px 6px;
  border-radius: 5px;
}

.move-san.current {
  color: var(--ink-dark);
  background: var(--gold);
  font-weight: 700;
}

.move-list-empty {
  padding: 14px 12px;
  font-size: 12px;
  letter-spacing: 2px;
  color: rgba(189, 168, 135, 0.55);
}

.board-banner {
  position: absolute;
  inset: 0;
  z-index: 5;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 20px;
  text-align: center;
  border-radius: var(--board-radius);
  background: rgba(14, 9, 4, 0.78);
  backdrop-filter: blur(3px);
  animation: bannerIn 0.35s ease both;
}

@keyframes bannerIn {
  from {
    opacity: 0;
    transform: scale(0.97);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.banner-title {
  margin: 0 0 10px;
  font-family: "Palatino Linotype", Palatino, "Noto Serif TC", serif;
  font-size: clamp(26px, 5vw, 40px);
  letter-spacing: 6px;
  color: var(--gold-bright);
  text-shadow: 0 3px 18px rgba(216, 180, 95, 0.4);
}

.overlay {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  background: rgba(10, 6, 3, 0.72);
  backdrop-filter: blur(3px);
  animation: bannerIn 0.2s ease both;
}

.modal-card {
  width: min(420px, 94vw);
  padding: 22px 22px 18px;
  border-radius: 14px;
  background: linear-gradient(175deg, var(--panel-2), var(--panel));
  border: 1px solid var(--gold-dim);
  box-shadow: 0 24px 70px rgba(0, 0, 0, 0.65);
}

.modal-title {
  margin: 0 0 8px;
  font-family: "Palatino Linotype", Palatino, "Noto Serif TC", serif;
  font-size: 24px;
  letter-spacing: 4px;
  color: var(--gold-bright);
}

.modal-text {
  margin: 0 0 14px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--muted);
}

.promo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(76px, 1fr));
  gap: 10px;
}

.promo-btn {
  appearance: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  min-height: 84px;
  padding: 10px 6px 8px;
  font: inherit;
  border-radius: 12px;
  border: 1px solid var(--edge);
  background: rgba(0, 0, 0, 0.28);
  color: var(--cream);
  cursor: pointer;
  transition: background 0.12s ease, border-color 0.12s ease, transform 0.12s ease;
}

.promo-btn .promo-glyph {
  font-size: 40px;
  line-height: 1.1;
}

.promo-btn .promo-name {
  font-size: 13px;
  letter-spacing: 2px;
  color: var(--muted);
}

.promo-btn:hover {
  background: rgba(242, 212, 136, 0.1);
  border-color: var(--gold-dim);
  transform: translateY(-2px);
}

.promo-btn:focus-visible {
  outline: 3px solid var(--gold-bright);
  outline-offset: 2px;
}

.modal-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.site-footer {
  padding: 16px 24px 26px;
  text-align: center;
}

.site-footer p {
  margin: 0;
  font-size: 12px;
  letter-spacing: 1.5px;
  color: rgba(189, 168, 135, 0.62);
}

@media (max-width: 1020px) {
  .layout {
    flex-direction: column;
    align-items: center;
    gap: 20px;
    padding: 6px 16px 26px;
  }

  .site-header {
    padding: 18px 16px 6px;
    justify-content: center;
    text-align: center;
  }

  .brand-tag {
    display: none;
  }

  .board-frame {
    --board-size: max(280px, min(560px, calc(100vw - 78px)));
    --glyph-base: calc(var(--board-size) / 10.2);
  }

  .rail {
    width: min(560px, 100%);
    flex: 0 1 auto;
  }

  .move-list {
    max-height: 180px;
  }
}

@media (max-width: 400px) {
  .action-row,
  .modal-actions {
    grid-template-columns: 1fr;
  }

  .status-main {
    font-size: 17px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .thinking i {
    animation: none;
    opacity: 0.9;
  }
}