:root{color-scheme:light dark;--color-bg:#ffffff;--color-fg:#1f2937;--color-muted:#6b7280;--color-border:#e5e7eb;--color-primary:#2563eb;--color-primary-hover:#1d4ed8;--color-success:#16a34a;--color-error:#dc2626;--color-warning:#d97706;--color-card-bg:#f9fafb}*{box-sizing:border-box}body{margin:0;color:var(--color-fg);background:var(--color-bg);font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Hiragino Sans,Noto Sans JP,sans-serif;line-height:1.6}a{color:var(--color-primary)}.page-body{padding:2rem 1.5rem 4rem}.page-body,main{max-width:720px;margin:0 auto}main{padding:2rem 1.5rem}h1{font-size:1.5rem}h2{font-size:1.15rem;margin-top:2rem}.navbar{border-bottom:1px solid var(--color-border);background:var(--color-card-bg)}.navbar-inner{max-width:720px;margin:0 auto;padding:.75rem 1.5rem;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:.5rem}.navbar-brand{font-weight:700;font-size:1.1rem;text-decoration:none;color:var(--color-fg)}.navbar-links{display:flex;align-items:center;gap:1rem;flex-wrap:wrap;font-size:.9rem}.navbar-links a{text-decoration:none;color:var(--color-fg)}.navbar-links a:hover{color:var(--color-primary)}.navbar-user{color:var(--color-muted)}.form{gap:1rem;max-width:420px}.form,.form-field{display:flex;flex-direction:column}.form-field{gap:.35rem}.form-field label{font-size:.9rem;font-weight:600}.form-field input,.form-field select,.form-field textarea{padding:.5rem .65rem;border:1px solid var(--color-border);border-radius:6px;font-size:1rem;background:var(--color-bg);color:var(--color-fg);font-family:inherit}.form-field textarea{resize:vertical}.honeypot-field{position:absolute;left:-9999px;top:-9999px;width:1px;height:1px;overflow:hidden}.form-hint{font-size:.8rem;color:var(--color-muted)}.checkbox-group{display:flex;flex-direction:column;gap:.4rem}.checkbox-group label{display:flex;align-items:center;gap:.5rem;font-weight:400;font-size:.95rem}.btn{display:inline-block;padding:.55rem 1.1rem;border-radius:6px;border:1px solid var(--color-primary);background:var(--color-primary);color:#fff;font-size:1rem;cursor:pointer;text-decoration:none;text-align:center}.btn:hover{background:var(--color-primary-hover);border-color:var(--color-primary-hover)}.btn:disabled{opacity:.55;cursor:not-allowed}.btn-secondary{background:var(--color-bg);color:var(--color-primary)}.btn-block{display:block;width:100%}.btn-link{background:none;border:none;color:var(--color-primary);cursor:pointer;padding:0;font-size:.9rem;text-decoration:underline}.card{border:1px solid var(--color-border);border-radius:8px;padding:1.25rem;background:var(--color-card-bg);margin-bottom:1rem}.card-link{display:block;text-decoration:none;color:inherit}.card-link:hover{border-color:var(--color-primary)}.stack{flex-direction:column;gap:1rem}.row,.stack{display:flex}.row{gap:.75rem;flex-wrap:wrap}.grid-2{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));grid-gap:1rem;gap:1rem}.alert-success,.status-ok{color:var(--color-success)}.alert-error,.status-error{color:var(--color-error)}.alert{padding:.75rem 1rem;border-radius:6px;border:1px solid;font-size:.9rem}.alert-error{background:#fef2f2}.alert-success{background:#f0fdf4}.badge{display:inline-block;padding:.15rem .5rem;border-radius:999px;font-size:.75rem;background:var(--color-border);color:var(--color-fg)}.badge-correct{background:#dcfce7;color:var(--color-success)}.badge-wrong{background:#fee2e2;color:var(--color-error)}.muted{color:var(--color-muted);font-size:.9rem}.choice-list{display:flex;flex-direction:column;gap:.6rem;margin:1rem 0}.choice-item{display:flex;align-items:flex-start;gap:.6rem;padding:.7rem .9rem;border:1px solid var(--color-border);border-radius:8px;cursor:pointer}.choice-item.selected,.choice-item:hover{border-color:var(--color-primary)}.choice-item.selected{background:#eff6ff}.choice-item.correct{border-color:var(--color-success);background:#f0fdf4}.choice-item.incorrect{border-color:var(--color-error);background:#fef2f2}.choice-item input{margin-top:.2rem}.progress-bar-outer{width:100%;height:10px;background:var(--color-border);border-radius:999px;overflow:hidden}.progress-bar-inner{height:100%;background:var(--color-primary)}.timer{font-feature-settings:"tnum";font-variant-numeric:tabular-nums;font-weight:700}.timer-warning{color:var(--color-error)}table{width:100%;border-collapse:collapse;font-size:.9rem}td,th{text-align:left;padding:.5rem .6rem;border-bottom:1px solid var(--color-border)}th{color:var(--color-muted);font-weight:600}@media (max-width:480px){table{display:block;overflow-x:auto;white-space:nowrap}}.site-footer{max-width:720px;margin:0 auto;padding:1rem 1.5rem 2rem;text-align:center;font-size:.85rem}.site-footer a{color:var(--color-muted);text-decoration:none}.site-footer a:hover{color:var(--color-primary)}