:root {
  --bg: #1b1b1f;
  --panel: #26262c;
  --panel-2: #2f2f37;
  --border: #3a3a44;
  --text: #e7e7ea;
  --muted: #a0a0ad;
  --accent: #6ea8fe;
  --accent-2: #4ade80;
  --danger: #f87171;
  --warn: #fbbf24;
  --light-sq: #f0d9b5;
  --dark-sq: #b58863;
  --radius: 10px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.45;
}

header.topbar {
  display: flex; align-items: center; gap: 16px;
  padding: 12px 20px; background: var(--panel); border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 10;
}
header.topbar h1 { font-size: 18px; margin: 0; letter-spacing: .3px; }
header.topbar h1 .accent { color: var(--accent); }
nav.tabs { display: flex; gap: 4px; margin-left: auto; flex-wrap: wrap; }
nav.tabs button {
  background: transparent; color: var(--muted); border: 1px solid transparent;
  padding: 7px 14px; border-radius: var(--radius); cursor: pointer; font-size: 14px;
}
nav.tabs button:hover { color: var(--text); background: var(--panel-2); }
nav.tabs button.active { color: var(--text); background: var(--panel-2); border-color: var(--border); }

main { max-width: 1200px; margin: 0 auto; padding: 20px; }
.screen { display: none; }
.screen.active { display: block; }

h2 { font-size: 20px; margin: 0 0 14px; }
h3 { font-size: 16px; margin: 0 0 10px; }
.muted { color: var(--muted); }
.small { font-size: 13px; }
.warn-box { background: #3a2f12; border: 1px solid #715d1d; color: #f3d68a; padding: 10px 14px; border-radius: var(--radius); font-size: 13px; margin-bottom: 16px; }
.hint { color: var(--muted); font-size: 13px; margin: 4px 0 0; }

.card { background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; margin-bottom: 16px; }
.row { display: flex; gap: 12px; flex-wrap: wrap; align-items: center; }
.row.between { justify-content: space-between; }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
@media (max-width: 700px) { .grid2 { grid-template-columns: 1fr; } }

label { display: block; font-size: 13px; color: var(--muted); margin-bottom: 4px; }
input[type=text], input[type=password], input[type=number], select, textarea {
  width: 100%; background: var(--panel-2); border: 1px solid var(--border); color: var(--text);
  padding: 9px 11px; border-radius: 8px; font-size: 14px; font-family: inherit;
}
input:focus, select:focus, textarea:focus { outline: none; border-color: var(--accent); }
.field { margin-bottom: 12px; }
.inline-field { display: flex; align-items: center; gap: 8px; }
.inline-field label { margin: 0; color: var(--text); }

button {
  font-family: inherit; font-size: 14px; cursor: pointer;
  background: var(--panel-2); color: var(--text); border: 1px solid var(--border);
  padding: 9px 16px; border-radius: 8px;
}
button:hover { border-color: var(--accent); }
button.primary { background: var(--accent); color: #0b1b34; border-color: var(--accent); font-weight: 600; }
button.primary:hover { filter: brightness(1.05); }
button.danger { color: var(--danger); }
button.ghost { background: transparent; }
button:disabled { opacity: .5; cursor: not-allowed; }
.btn-sm { padding: 5px 10px; font-size: 13px; }

/* ---- Board ---- */
.game-layout { display: grid; grid-template-columns: minmax(320px, 560px) 1fr; gap: 20px; align-items: start; }
@media (max-width: 900px) { .game-layout { grid-template-columns: 1fr; } }

.board {
  display: grid; grid-template-columns: repeat(8, 1fr); grid-template-rows: repeat(8, 1fr);
  width: 100%; aspect-ratio: 1 / 1; border: 3px solid #14140f; border-radius: 6px; overflow: hidden;
  user-select: none;
}
.sq { position: relative; display: flex; align-items: center; justify-content: center; }
.sq.light { background: var(--light-sq); }
.sq.dark { background: var(--dark-sq); }
.sq .piece { font-size: clamp(22px, 6.2vw, 46px); line-height: 1; }
.sq .piece.white { color: #fff; text-shadow: 0 1px 2px rgba(0,0,0,.45); }
.sq .piece.black { color: #1a1a1a; text-shadow: 0 1px 1px rgba(255,255,255,.25); }
.sq.last::after { content: ""; position: absolute; inset: 0; background: rgba(110,168,254,.32); }
.sq.selected::after { content: ""; position: absolute; inset: 0; background: rgba(74,222,128,.40); }
.sq.check::after { content: ""; position: absolute; inset: 0; background: radial-gradient(circle, rgba(248,113,113,.75), transparent 70%); }
.sq.dest::before { content: ""; position: absolute; width: 28%; height: 28%; border-radius: 50%; background: rgba(20,20,20,.35); z-index: 2; }
.sq.capture-dest::before { content: ""; position: absolute; inset: 6%; border: 4px solid rgba(20,20,20,.35); border-radius: 50%; z-index: 2; }
.sq .coord { position: absolute; font-size: 10px; color: rgba(0,0,0,.5); font-weight: 600; }
.sq .coord.rank { top: 2px; left: 3px; }
.sq .coord.file { bottom: 1px; right: 3px; }
.sq .piece { z-index: 3; }

.promo-overlay { position: fixed; inset: 0; background: rgba(0,0,0,.55); display: flex; align-items: center; justify-content: center; z-index: 100; }
.promo-box { background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius); padding: 12px; display: flex; gap: 8px; }
.promo-choice { font-size: 40px; padding: 6px 12px; line-height: 1; }

/* ---- Side panel ---- */
.panel-stack { display: flex; flex-direction: column; gap: 16px; }
.status-line { font-size: 15px; font-weight: 600; }
.players { display: flex; flex-direction: column; gap: 6px; }
.player-row { display: flex; align-items: center; gap: 8px; font-size: 14px; padding: 6px 8px; border-radius: 8px; background: var(--panel-2); }
.player-row.active { outline: 2px solid var(--accent); }
.player-row .dot { width: 14px; height: 14px; border-radius: 50%; border: 1px solid #000; }
.player-row .dot.w { background: #fff; }
.player-row .dot.b { background: #111; }

.thinking { display: flex; align-items: center; gap: 8px; color: var(--accent); font-size: 14px; min-height: 20px; }
.spinner { width: 14px; height: 14px; border: 2px solid var(--accent); border-top-color: transparent; border-radius: 50%; animation: spin .8s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

.movelog { max-height: 220px; overflow-y: auto; font-variant-numeric: tabular-nums; font-size: 14px; }
.movelog table { width: 100%; border-collapse: collapse; }
.movelog td { padding: 2px 8px; }
.movelog td.num { color: var(--muted); width: 36px; }
.movelog .ply { cursor: pointer; border-radius: 4px; padding: 1px 6px; }
.movelog .ply:hover { background: var(--panel-2); }
.movelog .ply.current { background: var(--accent); color: #0b1b34; }

.explain { background: var(--panel-2); border-radius: 8px; padding: 12px; font-size: 14px; }
.explain .who { font-weight: 600; margin-bottom: 4px; }
.explain .tools { color: var(--muted); font-size: 12px; margin-top: 8px; }

/* ---- Lists ---- */
.list-item { display: flex; align-items: center; gap: 12px; padding: 10px 12px; border: 1px solid var(--border); border-radius: 8px; margin-bottom: 8px; background: var(--panel-2); }
.list-item .grow { flex: 1; }
.tag { font-size: 12px; padding: 2px 8px; border-radius: 999px; background: var(--panel); border: 1px solid var(--border); color: var(--muted); }
.tag.win { color: var(--accent-2); }
.tag.loss { color: var(--danger); }
.tag.draw { color: var(--warn); }

.model-item { display: flex; align-items: center; gap: 10px; padding: 8px 10px; border: 1px solid var(--border); border-radius: 8px; margin-bottom: 6px; }
.model-item .grow { flex: 1; }

dialog { background: var(--panel); color: var(--text); border: 1px solid var(--border); border-radius: var(--radius); padding: 0; max-width: 520px; width: 92%; }
dialog::backdrop { background: rgba(0,0,0,.55); }
.dialog-body { padding: 18px; }
.dialog-actions { display: flex; justify-content: flex-end; gap: 8px; padding: 14px 18px; border-top: 1px solid var(--border); }

.empty { color: var(--muted); text-align: center; padding: 30px; }
pre.code { background: #15151a; border: 1px solid var(--border); border-radius: 8px; padding: 10px; overflow-x: auto; font-size: 12px; }
.banner-error { background: #3a1518; border: 1px solid #6e2329; color: #f3a3a3; padding: 10px 14px; border-radius: 8px; margin-bottom: 12px; font-size: 13px; }