:root {
  color-scheme: dark;
  --bg: #0d1311;
  --panel: #17211d;
  --panel-soft: #202d28;
  --ink: #f4f3ea;
  --muted: #9baaa3;
  --accent: #e6b85c;
  --green: #5f9d73;
  --light-square: #e5dcc9;
  --dark-square: #73917b;
  --board-size: min(68vw, 680px);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 15% 5%, rgba(95, 157, 115, .14), transparent 34rem),
    linear-gradient(135deg, #0b100e, var(--bg));
}

button, input, select { font: inherit; }
button, select { cursor: pointer; }

.app-shell { width: min(1180px, calc(100% - 40px)); margin: 0 auto; padding: 28px 0 40px; }
.masthead { display: flex; align-items: end; justify-content: space-between; margin-bottom: 24px; }
.masthead h1 { margin: 2px 0 0; font-family: Georgia, serif; font-size: clamp(2rem, 5vw, 3.7rem); line-height: .9; letter-spacing: -.04em; }
.masthead h1 span { color: var(--accent); }
.eyebrow, .label { margin: 0; color: var(--accent); font-size: .72rem; font-weight: 800; letter-spacing: .18em; }
.credit { margin: 0 0 4px; color: var(--muted); font-size: .85rem; }

.game-layout { display: grid; grid-template-columns: minmax(0, 1fr) 330px; gap: 26px; align-items: start; }
.board-column { min-width: 0; }
.player-strip { display: grid; grid-template-columns: 42px 1fr auto; gap: 11px; align-items: center; padding: 10px 2px; }
.player-strip strong, .player-strip span { display: block; }
.player-strip span { margin-top: 2px; color: var(--muted); font-size: .78rem; }
.player-strip time { font-variant-numeric: tabular-nums; font-size: 1.35rem; font-weight: 750; }
.avatar { display: grid; width: 40px; height: 40px; place-items: center; border: 1px solid #3c5148; border-radius: 10px; color: #121713; background: var(--accent); font-size: .78rem; font-weight: 900; }
.player-avatar { color: var(--ink); background: var(--panel-soft); }

.chessboard {
  display: grid;
  width: 100%;
  max-width: 760px;
  aspect-ratio: 1;
  grid-template-columns: repeat(8, minmax(0, 1fr));
  grid-template-rows: repeat(8, minmax(0, 1fr));
  overflow: hidden;
  border: 6px solid #293a33;
  border-radius: 5px;
  box-shadow: 0 24px 70px rgba(0, 0, 0, .35);
}

.square { position: relative; display: grid; width: 100%; height: 100%; min-width: 0; min-height: 0; overflow: hidden; padding: 0; place-items: center; border: 0; border-radius: 0; appearance: none; color: #172019; background: var(--light-square); line-height: 1; }
.square.dark { background: var(--dark-square); }
.square:hover { filter: brightness(1.04); }
.square.selected::after { position: absolute; inset: 5%; border: 4px solid rgba(230, 184, 92, .95); border-radius: 5px; content: ""; pointer-events: none; }
.square.last-move { box-shadow: inset 0 0 0 999px rgba(230, 184, 92, .28); }
.square.best-origin, .square.best-target { box-shadow: inset 0 0 0 999px rgba(67, 175, 226, .27); }
.square.best-origin::after, .square.best-target::after { position: absolute; z-index: 4; inset: 7%; border: 3px dashed rgba(214, 243, 255, .92); border-radius: 6px; content: ""; pointer-events: none; }
.square.best-target::after { border-style: solid; }
.square.in-check { box-shadow: inset 0 0 28px 8px rgba(211, 66, 66, .85); }
.square.legal-target::before { position: absolute; z-index: 2; width: 22%; aspect-ratio: 1; border-radius: 50%; background: rgba(15, 36, 27, .52); content: ""; pointer-events: none; }
.square.capture-target::before { width: 76%; border: clamp(5px, .7vw, 9px) solid rgba(15, 36, 27, .52); background: transparent; }
.piece { z-index: 1; display: block; max-width: 88%; max-height: 88%; font-family: "Segoe UI Symbol", "Noto Sans Symbols 2", "DejaVu Sans", serif; font-size: clamp(2rem, 7vw, 5rem); line-height: 1; transform: translateY(-2%); filter: drop-shadow(0 2px 1px rgba(0, 0, 0, .28)); }
.piece.white-piece { color: #fffdf5; text-shadow: 0 0 1px #172019, 0 1px 2px #172019; }
.coordinate { position: absolute; z-index: 3; color: rgba(21, 35, 28, .72); font-size: clamp(.5rem, 1.1vw, .72rem); font-weight: 800; pointer-events: none; }
.coordinate.rank { top: 4px; left: 5px; }
.coordinate.file { right: 5px; bottom: 3px; }

.sidebar { display: flex; min-height: 640px; flex-direction: column; gap: 12px; padding: 18px; border: 1px solid #2a3b34; border-radius: 16px; background: rgba(23, 33, 29, .92); box-shadow: 0 20px 60px rgba(0, 0, 0, .25); }
.mode-card, .status-card, .evaluation-card, .control-card, .analysis-card { padding: 16px; border-radius: 11px; background: var(--panel-soft); }
.mode-options { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin-top: 11px; }
.mode-options label { position: relative; display: block; min-width: 0; cursor: pointer; }
.mode-options input { position: absolute; opacity: 0; pointer-events: none; }
.mode-options span { display: block; height: 100%; padding: 10px; border: 1px solid #40534b; border-radius: 8px; color: var(--muted); background: #151f1b; }
.mode-options strong, .mode-options small { display: block; }
.mode-options strong { color: var(--ink); font-size: .78rem; }
.mode-options small { margin-top: 3px; font-size: .65rem; line-height: 1.3; }
.mode-options input:checked + span { border-color: var(--accent); background: rgba(230, 184, 92, .1); box-shadow: inset 0 0 0 1px var(--accent); }
.mode-options input:focus-visible + span { outline: 2px solid var(--ink); outline-offset: 2px; }
.status-card h2 { margin: 7px 0 4px; font-size: 1.2rem; }
.status-card > p:last-child, .evaluation-card > p, .control-card p { margin: 0; color: var(--muted); font-size: .78rem; line-height: 1.45; }
.evaluation-card > div:first-child { display: flex; align-items: end; justify-content: space-between; }
#evaluation { font-size: 1.35rem; font-variant-numeric: tabular-nums; }
.eval-track { height: 7px; margin: 12px 0 9px; overflow: hidden; border-radius: 10px; background: #111814; }
.eval-track span { display: block; width: 50%; height: 100%; background: var(--ink); transition: width .25s ease; }
.control-card label { display: block; margin-bottom: 9px; font-size: .83rem; font-weight: 750; }
.control-card select { width: 100%; padding: 10px; border: 1px solid #455a51; border-radius: 8px; color: var(--ink); background: #131c18; }
.control-card p { margin-top: 8px; }
.analysis-heading { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
#analysis-depth { color: var(--muted); font-size: .7rem; }
.analysis-card dl { margin: 13px 0; }
.analysis-card dl > div + div { margin-top: 12px; }
.analysis-card dt { color: var(--muted); font-size: .7rem; }
.analysis-card dd { margin: 4px 0 0; overflow-wrap: anywhere; color: var(--ink); font-size: .86rem; line-height: 1.45; }
#best-move { color: var(--accent); font-family: Georgia, serif; font-size: 1.45rem; font-weight: 800; }
.analysis-actions { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.analysis-actions button { min-height: 40px; padding: 8px; border: 1px solid #50675d; border-radius: 8px; color: var(--ink); background: #131c18; font-size: .75rem; font-weight: 750; }
.analysis-actions button:hover:not(:disabled) { border-color: var(--accent); }
.analysis-actions button:disabled { cursor: not-allowed; opacity: .45; }
.analysis-mode .player-strip time, .analysis-mode .control-card { display: none; }
.analysis-mode .sidebar { min-height: 0; }
.move-list { min-height: 100px; max-height: 170px; margin: 0; padding: 10px 10px 10px 42px; overflow: auto; border: 1px solid #2a3b34; border-radius: 10px; color: var(--muted); font-variant-numeric: tabular-nums; font-size: .8rem; line-height: 1.8; }
.move-list li { padding-left: 5px; }
.move-list li span { display: inline-block; min-width: 75px; color: var(--ink); }
.empty-history { list-style: none; margin-left: -28px; }
.restart-button, .modal button[type="submit"] { width: 100%; margin-top: auto; padding: 12px 16px; border: 0; border-radius: 9px; color: #111814; background: var(--accent); font-weight: 850; }
.restart-button:hover, .modal button[type="submit"]:hover { filter: brightness(1.08); }

.modal { width: min(430px, calc(100% - 32px)); padding: 0; border: 1px solid #3b5147; border-radius: 16px; color: var(--ink); background: var(--panel); box-shadow: 0 30px 90px #000; }
.modal::backdrop { background: rgba(2, 8, 5, .82); backdrop-filter: blur(6px); }
.modal form { padding: 28px; }
.modal h2 { margin: 8px 0; font-family: Georgia, serif; font-size: 1.8rem; }
.modal form > p:not(.eyebrow) { margin: 0 0 22px; color: var(--muted); line-height: 1.5; }
.modal label { display: block; margin-bottom: 7px; font-size: .8rem; font-weight: 750; }
.modal input { width: 100%; margin-bottom: 14px; padding: 12px; border: 1px solid #42584e; border-radius: 8px; color: var(--ink); background: #0f1713; outline: none; }
.modal input:focus { border-color: var(--accent); }
.promotion-options { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; margin-top: 18px; }
.promotion-options button[type="submit"] { margin: 0; padding: 12px 4px; font-size: 2.2rem; }
.result-modal { text-align: center; }

.thinking .ai-strip .avatar, .analysis-thinking .ai-strip .avatar { animation: pulse 1s ease-in-out infinite alternate; }
@keyframes pulse { to { box-shadow: 0 0 0 7px rgba(230, 184, 92, .13); transform: scale(1.03); } }

@media (max-width: 920px) {
  .app-shell { width: min(720px, calc(100% - 24px)); padding-top: 18px; }
  .game-layout { grid-template-columns: 1fr; }
  .sidebar { min-height: auto; }
  .move-list { max-height: 150px; }
}

@media (max-width: 520px) {
  .app-shell { width: 100%; padding: 14px 10px 24px; }
  .masthead { margin: 0 4px 14px; }
  .credit { max-width: 125px; text-align: right; }
  .chessboard { border-width: 3px; }
  .piece { font-size: clamp(1.75rem, 10.5vw, 3.5rem); }
  .sidebar { padding: 12px; }
  .mode-options { grid-template-columns: 1fr; }
  .analysis-actions { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; animation-duration: .01ms !important; transition-duration: .01ms !important; }
}