:root{color-scheme:dark;--bg:#10151c;--panel:#19212c;--muted:#a7b5c7;--ink:#f4f8fc;--accent:#b7f87b}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.5 system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}.shell{max-width:520px;margin:auto;padding:24px 24px max(24px,env(safe-area-inset-bottom))}header{display:flex;align-items:center;justify-content:space-between;gap:8px}.brand{display:flex;align-items:center;gap:6px;color:var(--ink);text-decoration:none;font-weight:750;letter-spacing:-.6px}.brand-light{color:var(--muted);font-weight:400}.brand-mark{display:grid;place-items:center;width:30px;height:30px;color:var(--bg);background:var(--accent);border-radius:9px;font-weight:900;margin-right:5px}.chip{font-size:11px;color:var(--muted);border:1px solid #344051;border-radius:30px;padding:4px 8px;white-space:nowrap}.intro{padding:40px 0 22px}.eyebrow{font-size:11px;letter-spacing:1.6px;font-weight:700;color:var(--accent);margin:0 0 13px}h1{font-size:58px;line-height:1.03;letter-spacing:-3px;margin:0 0 17px}.subline{color:var(--muted);font-size:15px;margin:0;line-height:1.7}.subline strong{color:var(--ink)}.stats{display:grid;grid-template-columns:repeat(3,1fr);border-top:1px solid #2e3948;border-bottom:1px solid #2e3948;padding:17px 0;margin-bottom:24px}.stats div{display:flex;flex-direction:column;gap:3px}.stats span{font-size:9px;letter-spacing:1px;color:var(--muted)}.stats strong{font-size:21px;font-weight:650}.puzzle{position:relative;isolation:isolate}.board{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;aspect-ratio:1}.tile{border:1px solid #374456;background:var(--panel);color:var(--ink);border-radius:17px;display:grid;place-items:center;min-width:0;cursor:pointer;position:relative;font:inherit;touch-action:manipulation}.tile:hover{border-color:var(--accent)}.tile.selected{background:#29422d;border-color:#8aba6a}.tile.head{box-shadow:inset 0 0 0 2px var(--accent)}.checkpoint{display:grid;place-items:center;width:30px;height:30px;background:#273443;border-radius:50%;font-size:16px;font-weight:800;position:relative;z-index:3}.selected .checkpoint{background:var(--accent);color:#172010}.path-overlay{position:absolute;inset:0;width:100%;height:100%;pointer-events:none;z-index:2}.path-overlay polyline{fill:none;stroke:var(--accent);stroke-width:7;stroke-linecap:round;stroke-linejoin:round;opacity:.7}.instruction{font-size:12px;color:var(--muted);text-align:center;margin:16px 0}.tools{display:flex;gap:10px}.secondary{border:1px solid #344153;background:transparent;color:var(--ink);border-radius:11px;padding:10px 15px;font:inherit;font-size:13px;cursor:pointer;min-height:44px}.tools>*{flex:1}button:disabled{opacity:.42;cursor:default}button:focus-visible,a:focus-visible{outline:3px solid #eaffd8;outline-offset:4px}.notice{font-size:12px;color:var(--accent);min-height:48px;display:flex;align-items:center;line-height:1.5;padding:6px 0}.primary{display:block;width:100%;border:0;background:var(--accent);color:#172010;border-radius:13px;min-height:51px;font-weight:800;font-size:15px;cursor:pointer}.save{display:block;width:100%;border:0;background:transparent;color:var(--ink);font-size:13px;padding:16px;cursor:pointer}.complete{background:#1b2d23;border:1px solid #416239;border-radius:14px;padding:20px;margin-bottom:18px}.complete h2{font-size:22px;letter-spacing:-.8px;line-height:1.2;margin:0 0 10px}.complete p:last-child{font-size:13px;color:var(--muted);margin:0}footer{display:flex;flex-wrap:wrap;justify-content:center;gap:8px;color:var(--muted);font-size:11px;border-top:1px solid #2e3948;padding-top:18px}footer button{border:0;background:none;color:var(--muted);font-size:11px;text-decoration:underline;cursor:pointer;min-height:28px}.privacy{color:var(--muted);font-size:13px;padding:20px 0}.privacy h2{font-size:19px;color:var(--ink)}[hidden]{display:none!important}@media(max-width:360px){.shell{padding:16px}.brand{font-size:14px}.chip{font-size:9px}h1{font-size:48px}.intro{padding-top:30px}.board{gap:7px}.tile{border-radius:13px}}@media(prefers-reduced-motion:no-preference){button{transition:background .12s,border-color .12s}}