:root{--bg: #161512;--panel: #262421;--panel-2: #302e2b;--text: #ededed;--muted: #9b958c;--accent: #629924;--accent-2: #4a8a1f;--light-sq: #f0d9b5;--dark-sq: #b58863;--good: #629924;--bad: #c0392b;--hint: #3692e7;--radius: 10px;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif}*{box-sizing:border-box}html,body{margin:0;background:var(--bg);color:var(--text);min-height:100vh}#app{max-width:720px;margin:0 auto;padding:16px 16px 48px}h1,h2{font-weight:650}button{font:inherit;cursor:pointer}.topbar{display:flex;align-items:center;gap:12px;margin-bottom:18px;min-height:40px}.topbar h2{margin:0;font-size:1.25rem}.btn-back{background:var(--panel-2);color:var(--text);border:none;border-radius:var(--radius);padding:8px 14px}.btn-back:hover{background:#3a3835}.spacer{flex:1}.menu-title{text-align:center;margin:8px 0 4px;font-size:1.8rem}.menu-sub{text-align:center;color:var(--muted);margin:0 0 24px}.menu-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:14px}.menu-card{background:var(--panel);border:1px solid #3a3835;border-radius:var(--radius);padding:18px;text-align:left;color:var(--text);transition:transform .08s ease,border-color .15s ease}.menu-card:hover{transform:translateY(-2px);border-color:var(--accent)}.menu-card .ico{font-size:1.8rem}.menu-card .title{font-weight:650;margin:8px 0 4px;font-size:1.05rem}.menu-card .desc{color:var(--muted);font-size:.85rem;line-height:1.35}.board-wrap{display:flex;justify-content:center;margin:8px auto 16px}.board{display:grid;grid-template-columns:repeat(8,1fr);grid-template-rows:repeat(8,1fr);width:min(92vmin,540px);aspect-ratio:1 / 1;border-radius:6px;overflow:hidden;box-shadow:0 6px 24px #00000073;-webkit-user-select:none;user-select:none;touch-action:manipulation}.square{position:relative;display:flex;align-items:center;justify-content:center}.square.light{background:var(--light-sq)}.square.dark{background:var(--dark-sq)}.board.interactive .square{cursor:pointer}.square:after,.square:before{position:absolute;font-size:clamp(7px,1.8vmin,11px);font-weight:700;opacity:.8}.board:not(.flipped) .square[data-rank="1"]:after,.board.flipped .square[data-rank="8"]:after{content:attr(data-file);right:3px;bottom:1px}.board:not(.flipped) .square[data-file=a]:before,.board.flipped .square[data-file=h]:before{content:attr(data-rank);left:3px;top:1px}.square.light:after,.square.light:before{color:var(--dark-sq)}.square.dark:after,.square.dark:before{color:var(--light-sq)}.board.coords-hidden .square:after,.board.coords-hidden .square:before{content:none}.square.correct{box-shadow:inset 0 0 0 4px var(--good)}.square.wrong{box-shadow:inset 0 0 0 4px var(--bad)}.square.target{box-shadow:inset 0 0 0 4px var(--good)}.square.selected{box-shadow:inset 0 0 0 4px var(--hint)}.square.lastmove{background-image:linear-gradient(#9bc70069,#9bc70069)}.square.hint{box-shadow:inset 0 0 0 4px var(--hint)}.piece{font-size:clamp(24px,9vmin,54px);line-height:1;pointer-events:none}.piece.white{color:#fff;text-shadow:0 0 2px #000,0 1px 2px #000}.piece.black{color:#111;text-shadow:0 0 2px #999}.hud{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-bottom:12px}.stat{background:var(--panel);border-radius:var(--radius);padding:8px 16px;text-align:center;min-width:78px}.stat .label{color:var(--muted);font-size:.72rem;text-transform:uppercase;letter-spacing:.04em}.stat .value{font-size:1.4rem;font-weight:700}.stat.timer.low .value{color:var(--bad)}.prompt{text-align:center;margin:6px 0 14px}.prompt .current{font-size:3rem;font-weight:800;letter-spacing:.02em}.prompt .next{color:var(--muted);font-size:1.1rem;margin-top:2px}.prompt .next b{color:var(--text)}.answer-row{display:flex;gap:16px;justify-content:center;margin:8px 0 16px}.answer-btn{border:none;border-radius:var(--radius);padding:18px 0;flex:1;max-width:200px;font-size:1.2rem;font-weight:700;transition:transform .06s ease,filter .15s ease}.answer-btn:active{transform:scale(.97)}.answer-btn.light{background:var(--light-sq);color:#222}.answer-btn.dark{background:#3a3024;color:#f0d9b5;border:1px solid #5a4a36}.answer-btn.flash-good{outline:4px solid var(--good)}.answer-btn.flash-bad{outline:4px solid var(--bad)}.controls{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin-top:8px}.btn{background:var(--panel-2);color:var(--text);border:1px solid #3a3835;border-radius:var(--radius);padding:10px 16px;font-weight:600}.btn:hover{background:#3a3835}.btn.primary{background:var(--accent);border-color:var(--accent);color:#fff}.btn.primary:hover{background:var(--accent-2)}.btn.toggle.on{background:var(--accent);border-color:var(--accent);color:#fff}.setup{background:var(--panel);border-radius:var(--radius);padding:18px;margin-bottom:16px}.setup h3{margin:0 0 12px}.option-group{margin-bottom:16px}.option-group>.label{color:var(--muted);font-size:.8rem;margin-bottom:6px}.option-buttons{display:flex;gap:8px;flex-wrap:wrap}.seg{background:var(--panel-2);border:1px solid #3a3835;color:var(--text);border-radius:var(--radius);padding:8px 14px;font-weight:600}.seg.on{background:var(--accent);border-color:var(--accent);color:#fff}.best-line{color:var(--muted);font-size:.8rem;margin-top:8px}.feedback{text-align:center;min-height:1.5em;font-weight:600;margin:6px 0}.feedback.good{color:var(--good)}.feedback.bad{color:var(--bad)}.notice{background:var(--panel);border-left:3px solid var(--hint);border-radius:6px;padding:10px 14px;color:var(--muted);font-size:.85rem;margin-bottom:14px;line-height:1.4}.result{background:var(--panel);border-radius:var(--radius);padding:24px;text-align:center;margin-bottom:16px}.result .big{font-size:3rem;font-weight:800;color:var(--accent)}.result .sub{color:var(--muted)}.result .record{color:var(--accent);font-weight:700;margin-top:8px}.menu-foot{text-align:center;margin-top:28px;color:var(--muted);font-size:.8rem}.menu-foot button{background:none;border:none;color:var(--muted);text-decoration:underline;padding:4px}.menu-foot button:hover{color:var(--text)}.tactics-meta{display:flex;justify-content:center;gap:18px;flex-wrap:wrap;color:var(--muted);font-size:.85rem;margin-bottom:8px}.turn-banner{text-align:center;font-size:1.05rem;margin-bottom:8px}.turn-banner b{color:var(--text)}.piece-list{display:grid;grid-template-columns:1fr 1fr;gap:8px 18px;background:var(--panel);border-radius:var(--radius);padding:14px 16px;margin-bottom:12px;font-size:.95rem;line-height:1.5}.piece-list .side-label{color:var(--muted);font-size:.75rem;text-transform:uppercase;letter-spacing:.04em}.move-history{text-align:center;font-family:ui-monospace,Cascadia Code,monospace;color:var(--muted);min-height:1.4em;margin:6px 0;word-break:break-word}.move-history b{color:var(--text)}@media (max-width: 480px){.piece-list{grid-template-columns:1fr}.prompt .current{font-size:2.4rem}}