:root{--bg: #0f172a;--panel: #1e293b;--card: #ffffff;--text: #0f172a;--muted: #64748b;--accent: #2563eb;--error: #dc2626;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif}*{box-sizing:border-box}body{margin:0;background:#f1f5f9;color:var(--text)}.center{min-height:100vh;display:grid;place-items:center}.card{background:var(--card);padding:2.5rem;border-radius:12px;box-shadow:0 10px 30px #00000014;text-align:center;max-width:380px;width:100%}.card h1{margin:0 0 .25rem}.muted{color:var(--muted)}.error{color:var(--error)}button{cursor:pointer;border:1px solid #cbd5e1;background:#fff;padding:.5rem 1rem;border-radius:8px;font-size:.95rem;margin-top:.5rem}button.primary{background:var(--accent);color:#fff;border-color:var(--accent);width:100%}.shell{min-height:100vh}.topbar{display:flex;justify-content:space-between;align-items:center;padding:.85rem 1.5rem;background:var(--bg);color:#fff}.topbar .muted{margin-right:1rem;color:#94a3b8}.topbar button{margin-top:0}main{padding:2rem 1.5rem;max-width:1000px;margin:0 auto}.grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:1.25rem;margin-top:1.5rem}.panel{background:#fff;border:1px solid #e2e8f0;border-radius:12px;padding:1.5rem}.panel h3{margin-top:0}