:root{--bg:#f6f7f4;--card:#fff;--ink:#1f2a2e;--muted:#6b7a80;--line:#dde3e0;--accent:#1f6f8b;--accent-ink:#fff;--ok:#2e7d4f;--near:#c77d0c;--retry:#b3402f;--font:"Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Noto Sans CJK JP", "Yu Gothic", "Meiryo", system-ui, sans-serif}*{box-sizing:border-box}html,body{background:var(--bg);color:var(--ink);font-family:var(--font);margin:0;padding:0;font-size:17px;line-height:1.6}a{color:var(--accent);text-decoration:none}header.top{background:var(--card);border-bottom:1px solid var(--line);justify-content:space-between;align-items:center;padding:12px 16px;display:flex}header.top .brand{letter-spacing:.02em;font-weight:700}header.top nav a,header.top nav button{margin-left:14px;font-size:15px}main{max-width:720px;margin:0 auto;padding:20px 16px 60px}h1{margin:0 0 12px;font-size:1.35rem}h2{margin:24px 0 8px;font-size:1.1rem}.card{background:var(--card);border:1px solid var(--line);border-radius:12px;margin:12px 0;padding:16px}.muted{color:var(--muted);font-size:.92rem}.row{flex-wrap:wrap;align-items:center;gap:10px;display:flex}button,.btn{font:inherit;border:1px solid var(--line);background:var(--card);color:var(--ink);cursor:pointer;border-radius:10px;min-height:44px;padding:10px 16px}button.primary,.btn.primary{background:var(--accent);color:var(--accent-ink);border-color:var(--accent);font-weight:600}button.big{padding:14px 22px;font-size:1.1rem}button:disabled{opacity:.5;cursor:default}button.on{outline:3px solid var(--accent);outline-offset:-3px}input,textarea{font:inherit;border:1px solid var(--line);background:#fff;border-radius:10px;width:100%;padding:12px}textarea{min-height:90px;font-size:1.15rem;line-height:1.7}label{color:var(--muted);margin:12px 0 4px;font-size:.95rem;display:block}.verdict{margin:6px 0;font-size:1.4rem;font-weight:700}.verdict.ok{color:var(--ok)}.verdict.near{color:var(--near)}.verdict.retry{color:var(--retry)}.tiles{border:1px dashed var(--line);background:#fff;border-radius:10px;flex-wrap:wrap;gap:8px;min-height:52px;padding:8px;display:flex}.tile{border:1px solid var(--line);cursor:pointer;background:#eef3f1;border-radius:8px;padding:8px 12px;font-size:1.1rem}.tile.used{opacity:.35}.answer{padding:8px 0;font-size:1.25rem}.diff{border-left:4px solid var(--near);background:#fff8ec;border-radius:6px;margin:6px 0;padding:8px 10px}.progress{background:var(--line);border-radius:4px;height:8px;overflow:hidden}.progress>div{background:var(--accent);height:100%}table{border-collapse:collapse;width:100%;font-size:.95rem}th,td{text-align:left;border-bottom:1px solid var(--line);vertical-align:top;padding:8px 6px}.credit{color:var(--muted);text-align:center;margin-top:40px;font-size:.8rem}.err{color:var(--retry)}