:root{--bg: #f4f6f3;--bg-tint: #e9ede8;--surface: #ffffff;--surface-2: #f0f3ef;--line: #dde3dc;--text: #17201b;--muted: #66756c;--accent: #2f7a5b;--accent-soft: #d8ece1;--accent-text: #ffffff;--good: #2f7a5b;--good-soft: #d8ece1;--bad: #b23b30;--bad-soft: #f7dedb;--warn: #a9761c;--sq-light: #eeeed6;--sq-dark: #7d9b74;--shadow: 0 1px 2px rgba(16, 32, 24, .06), 0 8px 24px rgba(16, 32, 24, .07);--radius: 14px;--radius-sm: 10px;color-scheme:light}:root[data-theme=dark]{--bg: #101613;--bg-tint: #161d19;--surface: #18211c;--surface-2: #1f2a24;--line: #2a352e;--text: #e7efe9;--muted: #93a49a;--accent: #55b78a;--accent-soft: #1d372c;--accent-text: #06120c;--good: #55b78a;--good-soft: #1d372c;--bad: #e0796b;--bad-soft: #3a201c;--warn: #d6a44b;--sq-light: #cdd3bd;--sq-dark: #5e7a58;--shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 10px 30px rgba(0, 0, 0, .35);color-scheme:dark}*{box-sizing:border-box}html,body,#root{height:100%}body{margin:0;background:var(--bg);color:var(--text);font-family:ui-sans-serif,-apple-system,BlinkMacSystemFont,Segoe UI,Inter,Roboto,Helvetica Neue,sans-serif;font-size:16px;line-height:1.45;-webkit-font-smoothing:antialiased;-webkit-tap-highlight-color:transparent;overscroll-behavior-y:contain}button{font:inherit;color:inherit;border:none;background:none;cursor:pointer;touch-action:manipulation}h1,h2,h3{margin:0;font-weight:650;letter-spacing:-.02em}.app{min-height:100%;display:flex;flex-direction:column;align-items:center;padding:max(12px,env(safe-area-inset-top)) 12px calc(12px + env(safe-area-inset-bottom))}.screen{width:100%;max-width:480px;flex:1;display:flex;flex-direction:column;gap:14px}.screen--wide{max-width:560px}.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:16px;box-shadow:var(--shadow)}.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:48px;padding:0 18px;border-radius:var(--radius-sm);background:var(--surface-2);border:1px solid var(--line);font-weight:600;transition:transform .08s ease,background .15s ease,opacity .15s ease}.btn:active{transform:scale(.98)}.btn:disabled{opacity:.45;cursor:default}.btn--primary{background:var(--accent);border-color:var(--accent);color:var(--accent-text)}.btn--ghost{background:transparent}.btn--block{width:100%}.btn--lg{min-height:56px;font-size:1.05rem}.row{display:flex;gap:10px;align-items:center}.row--wrap{flex-wrap:wrap}.spacer{flex:1}.muted{color:var(--muted)}.small{font-size:.85rem}.center{text-align:center}.stack{display:flex;flex-direction:column;gap:10px}.pill{display:inline-flex;align-items:center;gap:6px;padding:4px 10px;border-radius:999px;background:var(--surface-2);border:1px solid var(--line);font-size:.82rem;font-weight:600;white-space:nowrap}.pill--accent{background:var(--accent-soft);border-color:transparent;color:var(--accent)}.board-wrap{width:100%;display:flex;justify-content:center}.board{--coord: 16px;width:100%;max-width:420px;display:grid;grid-template-columns:var(--coord) 1fr;grid-template-rows:1fr var(--coord);gap:2px;-webkit-user-select:none;user-select:none}.board--sm{max-width:260px;--coord: 12px}.board__grid{display:grid;grid-template-columns:repeat(8,1fr);grid-template-rows:repeat(8,1fr);aspect-ratio:1;border-radius:8px;overflow:hidden;border:1px solid var(--line)}.board__ranks,.board__files{display:grid;font-size:.62rem;font-weight:700;color:var(--muted)}.board__ranks{grid-template-rows:repeat(8,1fr);align-items:center;justify-items:center}.board__files{grid-column:2;grid-template-columns:repeat(8,1fr);justify-items:center}.sq{position:relative;display:flex;align-items:center;justify-content:center;font-size:clamp(18px,6.2vw,30px);line-height:1;background:var(--sq-dark);transition:background .15s ease}.board--sm .sq{font-size:18px}.sq--light{background:var(--sq-light)}.sq--tappable{cursor:pointer}.sq--tappable:active{filter:brightness(1.12)}.sq__piece{color:#101613;text-shadow:0 1px 0 rgba(255,255,255,.25)}.sq__piece--black{color:#14100e;text-shadow:0 1px 0 rgba(255,255,255,.22)}.sq__piece--white{color:#fdfdfa;text-shadow:0 0 1px #14100e,1px 0 0 #14100e,-1px 0 0 #14100e,0 1px 0 #14100e,0 -1px 0 #14100e}.sq__piece--knight{color:var(--accent);text-shadow:0 0 0 rgba(0,0,0,0);filter:drop-shadow(0 1px 1px rgba(0,0,0,.35))}.sq--knight:after{content:"";position:absolute;top:6%;right:6%;bottom:6%;left:6%;border:3px solid var(--accent);border-radius:50%;opacity:.85}.sq--highlight{background:#e6c96a}.sq--new:after{content:"";position:absolute;top:4%;right:4%;bottom:4%;left:4%;border:3px solid #d9534f;border-radius:6px;animation:pulse 1.1s ease-in-out infinite}.sq--used:after{content:"";position:absolute;top:18%;right:18%;bottom:18%;left:18%;border:2px dashed rgba(20,30,24,.55);border-radius:50%}.sq--danger:before{content:"";position:absolute;top:0;right:0;bottom:0;left:0;background:#be3c2d47}.sq--dot:before{content:"";position:absolute;width:26%;height:26%;border-radius:50%;background:#2f7a5bbf}.sq__coord{position:absolute;inset:auto 2px 1px auto;font-size:.5rem;font-weight:700;color:#141e1873}@keyframes pulse{0%,to{opacity:1}50%{opacity:.35}}.hud{display:flex;align-items:center;gap:8px;flex-wrap:wrap}.hearts{letter-spacing:2px;font-size:.95rem}.heart--gone{opacity:.25}.jumpbar{display:flex;gap:5px}.jumpbar__dot{width:20px;height:6px;border-radius:3px;background:var(--line)}.jumpbar__dot--on{background:var(--accent)}.headline{text-align:center;padding:8px 0 2px}.headline__label{font-size:.78rem;text-transform:uppercase;letter-spacing:.14em;color:var(--muted);font-weight:700}.headline__square{font-size:clamp(2.6rem,14vw,3.6rem);font-weight:700;letter-spacing:-.03em;line-height:1.05;font-variant-numeric:tabular-nums}.headline__square--hidden{color:var(--muted);font-size:clamp(1.5rem,7vw,2rem)}.prompt{text-align:center;font-size:1.02rem;font-weight:600}.prompt__sub{font-weight:500;color:var(--muted);font-size:.9rem}.feedback{min-height:46px;display:flex;align-items:center;justify-content:center;text-align:center;padding:8px 12px;border-radius:var(--radius-sm);font-size:.93rem;font-weight:550;border:1px solid transparent}.feedback--good{background:var(--good-soft);color:var(--good);animation:flash .4s ease}.feedback--bad{background:var(--bad-soft);color:var(--bad);animation:shake .4s ease}.feedback--info{background:var(--surface-2);color:var(--muted)}@keyframes flash{0%{background:var(--good);color:var(--accent-text)}to{background:var(--good-soft)}}@keyframes shake{0%,to{transform:translate(0)}20%{transform:translate(-7px)}40%{transform:translate(6px)}60%{transform:translate(-4px)}80%{transform:translate(2px)}}.chips{display:flex;flex-wrap:wrap;gap:6px;justify-content:center;min-height:34px}.chip{padding:5px 11px;border-radius:999px;background:var(--accent-soft);color:var(--accent);font-weight:700;font-size:.9rem;animation:pop .22s ease}.chip--ghost{background:transparent;border:1px dashed var(--line);color:var(--muted);font-weight:600}@keyframes pop{0%{transform:scale(.7);opacity:0}}.entry{display:flex;flex-direction:column;gap:10px}.entry__field{display:flex;align-items:center;justify-content:center;gap:2px;height:64px;border-radius:var(--radius-sm);border:2px solid var(--line);background:var(--surface);font-size:2rem;font-weight:700;letter-spacing:.16em;text-transform:uppercase;transition:border-color .15s ease}.entry__field--active{border-color:var(--accent)}.entry__field--bad{border-color:var(--bad);animation:shake .4s ease}.entry__placeholder{color:var(--muted);font-size:.95rem;font-weight:500;letter-spacing:0;text-transform:none}.caret{display:inline-block;width:2px;height:1.6rem;background:var(--accent);animation:blink 1.1s steps(1) infinite}@keyframes blink{50%{opacity:0}}.keypad{display:flex;flex-direction:column;gap:8px}.keypad__row{display:grid;grid-template-columns:repeat(8,1fr);gap:6px}.key{min-height:52px;border-radius:var(--radius-sm);background:var(--surface);border:1px solid var(--line);font-size:1.15rem;font-weight:700;text-transform:uppercase;transition:transform .06s ease,background .12s ease}.key:active{transform:scale(.94);background:var(--accent-soft)}.key--on{background:var(--accent);border-color:var(--accent);color:var(--accent-text)}.key:disabled{opacity:.35}.keypad__row--ranks .key{font-variant-numeric:tabular-nums}.overlay{position:fixed;top:0;right:0;bottom:0;left:0;z-index:30;display:flex;align-items:center;justify-content:center;padding:16px;background:#0a100da8;animation:fade .15s ease}@keyframes fade{0%{opacity:0}}.overlay__panel{width:100%;max-width:440px;max-height:92vh;overflow-y:auto;background:var(--surface);border-radius:var(--radius);border:1px solid var(--line);padding:18px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:14px}.toggle{display:flex;width:100%;text-align:left;align-items:center;gap:12px;padding:10px 0;border-bottom:1px solid var(--line)}.toggle:last-child{border-bottom:none}.toggle__text{flex:1}.switch{width:50px;height:30px;border-radius:999px;background:var(--line);position:relative;flex:none;transition:background .18s ease}.switch--on{background:var(--accent)}.switch:after{content:"";position:absolute;top:3px;left:3px;width:24px;height:24px;border-radius:50%;background:#fff;transition:transform .18s ease;box-shadow:0 1px 3px #0000004d}.switch--on:after{transform:translate(20px)}.segmented{display:grid;grid-auto-flow:column;gap:4px;padding:4px;background:var(--surface-2);border-radius:var(--radius-sm)}.segmented button{min-height:38px;border-radius:8px;font-size:.88rem;font-weight:600;color:var(--muted)}.segmented button[aria-pressed=true]{background:var(--surface);color:var(--text);box-shadow:var(--shadow)}.brand{text-align:center;padding:18px 0 6px}.brand__mark{font-size:3rem;line-height:1;color:var(--accent)}.brand__title{font-size:1.9rem;margin-top:6px}.brand__tag{color:var(--muted);font-size:.95rem}.stats-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:10px}.stat{background:var(--surface-2);border-radius:var(--radius-sm);padding:10px 12px}.stat__value{font-size:1.35rem;font-weight:700;font-variant-numeric:tabular-nums}.stat__label{font-size:.76rem;color:var(--muted);text-transform:uppercase;letter-spacing:.08em;font-weight:650}.levels{display:grid;grid-template-columns:repeat(auto-fill,minmax(58px,1fr));gap:8px}.level-btn{min-height:48px;border-radius:var(--radius-sm);border:1px solid var(--line);background:var(--surface-2);font-weight:700}.level-btn--locked{opacity:.35;cursor:default}.how{display:flex;flex-direction:column;gap:12px}.how__steps{margin:0;padding-left:18px;color:var(--muted);font-size:.92rem}.how__steps li{margin-bottom:6px}.demo__caption{text-align:center;font-size:.9rem;font-weight:600;min-height:22px}.screen--tap{gap:8px}.screen--tap .headline{padding:0}.screen--tap .headline__square{font-size:clamp(1.8rem,8vw,2.2rem)}.screen--tap .prompt{font-size:.94rem}.screen--tap .feedback{min-height:38px;font-size:.86rem}.screen--tap .board{max-width:340px}.screen--tap .sq__coord{display:none}.notice{border-left:3px solid var(--warn);background:var(--surface-2);padding:10px 12px;border-radius:8px;font-size:.88rem}@media (min-width: 700px){.app{padding-top:28px}.key{min-height:46px}}@media (prefers-reduced-motion: reduce){*{animation-duration:.01ms!important;transition-duration:.01ms!important}}