/* Vai trò file: Bố cục/form/bàn cờ của trang demo, không có logic luật. */
:root{font-family:system-ui;color:#e8edf2;background:#111820}body{margin:0}main{max-width:1250px;margin:auto;padding:18px}.toolbar,.statusbar{display:flex;gap:8px;flex-wrap:wrap;margin:10px 0}.statusbar span,.notice{background:#18232d;border:1px solid #34495a;border-radius:5px;padding:8px}.notice{color:#d7c88e}input,select,button{background:#202b36;color:#e8edf2;border:1px solid #475766;border-radius:5px;padding:8px}button{cursor:pointer}button:hover{background:#304255}button:disabled{opacity:.45;cursor:not-allowed}.layout{display:grid;grid-template-columns:auto 1fr;gap:18px}.board{display:grid;grid-template-columns:repeat(9,54px);grid-template-rows:repeat(10,54px);border:2px solid #b99155;background:#d7b477}.cell{border:1px solid #7d623a;display:grid;place-items:center;font-size:11px;text-align:center;color:#1a1712;user-select:none}.cell.legal{background:#a4d48b}.piece{width:42px;height:42px;border-radius:50%;display:grid;place-items:center;background:#f2dfb9;border:2px solid #252525;font-weight:700}.piece.black{color:#111}.piece.red{color:#a91515}.piece.selected{box-shadow:0 0 0 4px #42a5f5}pre{height:560px;overflow:auto;background:#080d12;padding:12px;white-space:pre-wrap}.history{margin-top:18px;border-top:1px solid #34495a;padding-top:10px}#historyList{display:grid;gap:6px}.historyItem{text-align:left;font-family:monospace}@media(max-width:900px){.layout{grid-template-columns:1fr}.board{grid-template-columns:repeat(9,36px);grid-template-rows:repeat(10,36px)}.cell{font-size:8px}.piece{width:30px;height:30px}}