:root{
  --bg:#0b1220;--card:#0e1526;--fg:#e2e8f0;--muted:#94a3b8;--primary:#2563eb;--ok:#22c55e;--err:#ef4444;--warn:#f59e0b;
  --mono: ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html,body{height:100%}
body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;background:#0b1220;color:var(--fg)}
.wrap{max-width:980px;margin:0 auto;padding:24px;display:grid;gap:16px}
.card{background:linear-gradient(180deg,#0f172a 0%,#0e1526 100%);border:1px solid rgba(148,163,184,.18);border-radius:16px;padding:16px;box-shadow:0 12px 30px rgba(0,0,0,.25)}
h1,h2,h3{margin:0 0 10px}
p{margin:6px 0 0;color:var(--muted)}
.btn{display:inline-flex;align-items:center;gap:8px;background:linear-gradient(180deg,#2563eb,#1d4ed8);border:1px solid rgba(37,99,235,.35);border-radius:10px;color:white;padding:10px 14px;text-decoration:none;cursor:pointer}
.btn[disabled]{opacity:.6;cursor:not-allowed}
.btn.secondary{background:#0b1220;border-color:rgba(148,163,184,.25);color:var(--fg)}
.center{display:grid;place-items:center}
.hidden{display:none}
#anchor{min-height:180px;border:1px dashed rgba(148,163,184,.25);border-radius:12px;display:grid;place-items:center;background:rgba(2,6,23,.25);padding:8px}
.log{font-family:var(--mono);background:#0a1120;border-radius:12px;border:1px solid rgba(148,163,184,.18);padding:10px;white-space:pre-wrap}
.options{display:grid;gap:8px;margin-top:8px}
.opt{padding:12px;border-radius:10px;background:#0b1220;border:1px solid rgba(148,163,184,.25);cursor:pointer}
.opt.correct{border-color:rgba(34,197,94,.6);background:rgba(34,197,94,.1)}
.opt.wrong{border-color:rgba(239,68,68,.6);background:rgba(239,68,68,.08)}
.notice{font-size:12px;color:var(--muted)}
a{color:#60a5fa}
.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:16px}
.blog-card{display:flex;flex-direction:column;gap:8px}
.blog-card h3{margin:0}
.blog-card p{margin:0;color:var(--muted)}
.small{font-size:12px;color:var(--muted)}