:root{--bg: #0f1115;--card: #1a1d24;--line: #2a2e38;--text: #e8eaf0;--muted: #9aa0ac;--accent: #4f8cff;--good: #38d39f;color-scheme:dark}*{box-sizing:border-box}body{margin:0;font-family:Pretendard,system-ui,-apple-system,Segoe UI,sans-serif;background:var(--bg);color:var(--text);line-height:1.6}a{color:var(--accent);text-decoration:none}.container{max-width:760px;margin:0 auto;padding:24px 20px 80px}header.nav{display:flex;gap:18px;align-items:center;padding:16px 20px;border-bottom:1px solid var(--line)}header.nav .brand{font-weight:700;font-size:18px}header.nav nav{display:flex;gap:16px;margin-left:auto}.card{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:20px;margin:16px 0}h1{font-size:28px;margin:8px 0 4px}h2{font-size:20px;margin:0 0 12px}.muted{color:var(--muted);font-size:14px}label{display:block;font-size:14px;color:var(--muted);margin:12px 0 4px}input,select{width:100%;padding:10px 12px;border-radius:10px;border:1px solid var(--line);background:#11141b;color:var(--text);font-size:15px}.row{display:flex;gap:12px}.row>*{flex:1}button.primary{margin-top:18px;width:100%;padding:12px;border:0;border-radius:10px;background:var(--accent);color:#fff;font-size:16px;font-weight:600;cursor:pointer}button.primary:disabled{opacity:.5;cursor:default}.result{border-color:var(--accent)}.metric{font-size:32px;font-weight:700;color:var(--good)}.tag{display:inline-block;font-size:13px;padding:2px 8px;border-radius:999px;background:#21262f;color:var(--muted);margin-left:6px}ul.notes{padding-left:18px;margin:8px 0}.error{color:#ff6b6b;font-size:14px;margin-top:10px}.disclaimer{font-size:12px;color:var(--muted);margin-top:14px}.feature-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px}@media (max-width: 560px){.feature-grid{grid-template-columns:1fr}.row{flex-direction:column}}