:root{--bg:#f6fbff;--surface:#ffffff;--ink:#172033;--muted:#617084;--line:#d8e6f2;--blue:#1d4ed8;--blue2:#0f766e;--soft:#eaf4ff;--warn:#f59e0b;--shadow:0 18px 50px rgba(23,32,51,.10);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:var(--bg)}*{box-sizing:border-box}body{margin:0;background:linear-gradient(180deg,#eef7ff 0,#fff 42%,#f8fbff 100%);color:var(--ink)}a{color:inherit}.osp-shell{width:min(1120px,calc(100% - 32px));margin-inline:auto}.osp-skip{position:absolute;left:-999px;top:8px;background:#fff;padding:10px 14px;border-radius:999px}.osp-skip:focus{left:14px;z-index:9}.osp-top{position:sticky;top:0;z-index:5;background:rgba(255,255,255,.92);backdrop-filter:blur(16px);border-bottom:1px solid var(--line)}.osp-nav{height:72px;display:flex;align-items:center;justify-content:space-between;gap:24px}.osp-brand{display:flex;align-items:center;gap:10px;text-decoration:none;font-weight:900;letter-spacing:-.02em}.osp-brand span span{color:var(--blue)}.osp-mark{display:grid;place-items:center;width:38px;height:38px;border-radius:12px;background:linear-gradient(135deg,var(--blue),#38bdf8);color:#fff;box-shadow:0 10px 22px rgba(29,78,216,.25)}.osp-nav nav{display:flex;align-items:center;gap:22px;font-weight:800;font-size:14px}.osp-nav nav a{text-decoration:none;color:#273449}.osp-nav nav a:hover{color:var(--blue)}.osp-menu{display:none;border:1px solid var(--line);background:#fff;border-radius:10px;padding:9px 12px;font-weight:800}.osp-hero{padding:72px 0 52px;border-bottom:1px solid var(--line)}.osp-hero-grid{display:grid;grid-template-columns:minmax(0,1.1fr) 360px;gap:44px;align-items:center}.osp-kicker{display:inline-block;font-size:12px;text-transform:uppercase;letter-spacing:.16em;font-weight:900;color:var(--blue2);margin-bottom:14px}.osp-hero h1{font-size:clamp(42px,6vw,76px);line-height:.95;letter-spacing:-.055em;margin:0 0 20px}.osp-hero p{font-size:19px;line-height:1.7;color:var(--muted);max-width:680px;margin:0 0 28px}.osp-hero-actions{display:flex;flex-wrap:wrap;gap:12px}.osp-button{border:0;border-radius:14px;padding:13px 18px;font-weight:900;text-decoration:none;cursor:pointer;font-size:15px}.osp-button--primary{background:var(--blue);color:#fff;box-shadow:0 14px 30px rgba(29,78,216,.22)}.osp-button--ghost{background:#fff;color:var(--ink);border:1px solid var(--line)}.osp-score-card{background:radial-gradient(circle at top left,#67e8f9 0,#2563eb 38%,#1e293b 100%);color:#fff;border-radius:34px;padding:34px;min-height:250px;display:flex;flex-direction:column;justify-content:center;box-shadow:var(--shadow);position:relative;overflow:hidden}.osp-score-card:after{content:"";position:absolute;right:-44px;bottom:-44px;width:180px;height:180px;border:28px solid rgba(255,255,255,.14);border-radius:38px;transform:rotate(12deg)}.osp-score-card span{font-weight:900;text-transform:uppercase;letter-spacing:.16em;font-size:12px}.osp-score-card strong{font-size:44px;line-height:1;margin:18px 0 10px}.osp-score-card small{color:#dbeafe;font-weight:700}.osp-tool{padding:64px 0}.osp-tool-head{display:grid;grid-template-columns:minmax(0,1fr) auto;gap:24px;align-items:end;margin-bottom:20px}.osp-tool h2,.osp-steps h2,.osp-faq h2{font-size:clamp(28px,4vw,44px);line-height:1.05;letter-spacing:-.035em;margin:0 0 10px}.osp-tool p,.osp-steps p{color:var(--muted);line-height:1.65;margin:0}.osp-stats{display:flex;gap:10px;flex-wrap:wrap;justify-content:flex-end}.osp-stats span{background:#fff;border:1px solid var(--line);border-radius:14px;padding:12px 14px;color:var(--muted);font-size:13px}.osp-stats b{display:block;color:var(--ink);font-size:18px}.osp-game-wrap{display:grid;grid-template-columns:280px minmax(0,1fr);gap:18px}.osp-side-panel,.osp-board-panel{background:#fff;border:1px solid var(--line);border-radius:28px;box-shadow:var(--shadow)}.osp-side-panel{padding:22px;align-self:start;display:grid;gap:12px}.osp-side-panel label{display:grid;gap:8px;font-weight:900}.osp-side-panel select{width:100%;border:1px solid var(--line);border-radius:12px;padding:12px;background:#fff;font:inherit}.osp-side-panel p{font-size:14px}.osp-board-panel{padding:22px}.osp-status{min-height:42px;display:flex;align-items:center;background:var(--soft);border-radius:16px;padding:10px 14px;font-weight:800;color:#173b70;margin-bottom:14px}.osp-board{display:grid;grid-template-columns:repeat(9,1fr);border:3px solid #172033;background:#172033;border-radius:18px;overflow:hidden;max-width:630px;margin:auto}.osp-cell{aspect-ratio:1;border:1px solid #dbe7f3;background:#fff;display:grid;place-items:center;font-weight:900;font-size:clamp(18px,3vw,30px);cursor:pointer;color:#172033}.osp-cell:nth-child(3n){border-right:3px solid #172033}.osp-cell:nth-child(n+19):nth-child(-n+27),.osp-cell:nth-child(n+46):nth-child(-n+54){border-bottom:3px solid #172033}.osp-cell:nth-child(9n){border-right:1px solid #dbe7f3}.osp-cell.is-given{background:#eef6ff;color:#0f3d82}.osp-cell.is-selected{background:#fef3c7;outline:3px solid var(--warn);z-index:1}.osp-cell.is-error{background:#fee2e2;color:#b91c1c}.osp-cell.is-same{background:#e0f2fe}.osp-numpad{display:grid;grid-template-columns:repeat(9,1fr);gap:8px;margin-top:14px}.osp-numpad button{border:1px solid var(--line);background:#fff;border-radius:14px;padding:13px 0;font-weight:900;cursor:pointer}.osp-numpad button:hover{background:var(--blue);color:#fff}.osp-steps{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;padding:20px 0 58px}.osp-steps article{background:#fff;border:1px solid var(--line);border-radius:24px;padding:24px}.osp-steps span{display:grid;place-items:center;width:36px;height:36px;background:var(--blue2);color:#fff;border-radius:50%;font-weight:900;margin-bottom:18px}.osp-steps h2{font-size:22px}.osp-article{padding-bottom:40px}.osp-prose{background:#fff;border:1px solid var(--line);border-radius:28px;padding:34px;box-shadow:0 12px 38px rgba(23,32,51,.06)}.osp-prose h2{font-size:28px;letter-spacing:-.025em;margin:0 0 12px}.osp-prose section+section{margin-top:28px}.osp-prose p{line-height:1.75;color:#3d4c60}.osp-faq{padding:32px 0 76px}.osp-faq header{text-align:center;margin-bottom:20px}.osp-faq header span{font-weight:900;color:var(--blue2);letter-spacing:.14em}.osp-faq details{background:#fff;border:1px solid var(--line);border-radius:18px;padding:18px 20px;margin-bottom:12px}.osp-faq summary{font-weight:900;cursor:pointer}.osp-faq p{color:var(--muted);line-height:1.7}.osp-page-title{padding:62px 0 24px}.osp-page-title>p{text-transform:uppercase;letter-spacing:.14em;font-weight:900;color:var(--blue2)}.osp-page-title h1{font-size:clamp(36px,5vw,64px);letter-spacing:-.05em;margin:0 0 14px}.osp-intro{max-width:780px;color:var(--muted);font-size:18px;line-height:1.7}.osp-page-body{padding:0 0 80px}.osp-footer{border-top:1px solid var(--line);background:#fff;padding:28px 0}.osp-footer-grid{display:flex;justify-content:space-between;gap:24px;align-items:center}.osp-footer p{margin:0;color:var(--muted)}.osp-footer nav{display:flex;gap:16px;flex-wrap:wrap}.osp-footer a{text-decoration:none;font-weight:800;color:#334155}@media (max-width:820px){.osp-menu{display:block}.osp-nav nav{display:none;position:absolute;left:16px;right:16px;top:72px;background:#fff;border:1px solid var(--line);border-radius:18px;padding:14px;box-shadow:var(--shadow)}.osp-top.open nav{display:grid}.osp-hero{padding:42px 0}.osp-hero-grid,.osp-tool-head,.osp-game-wrap,.osp-steps{grid-template-columns:1fr}.osp-hero h1{font-size:44px}.osp-score-card{min-height:180px}.osp-stats{justify-content:stretch}.osp-stats span{flex:1}.osp-board-panel{padding:12px;border-radius:20px}.osp-cell{font-size:20px}.osp-numpad{grid-template-columns:repeat(5,1fr)}.osp-footer-grid{display:grid}.osp-prose{padding:22px}}