:root{--bg: #f4f5f7;--card: #ffffff;--text: #1c1f24;--muted: #5b6270;--border: #d7dbe1;--accent: #2b5ea7;--error-bg: #fdecec;--error: #8a1c1c}*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font:16px/1.5 system-ui,-apple-system,Segoe UI,sans-serif}#app{max-width:640px;margin:0 auto;padding:24px 16px 48px;display:flex;flex-direction:column;gap:16px}.card{background:var(--card);border:1px solid var(--border);border-radius:10px;padding:20px}.center{text-align:center}h1{margin:0 0 4px;font-size:22px}p{margin:0}.muted{color:var(--muted);font-size:14px}.stack{display:flex;flex-direction:column;gap:14px}.stack-sm{display:flex;flex-direction:column;gap:6px;font-size:14px;font-weight:500}.row{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:12px}input{min-height:44px;padding:0 12px;border:1px solid var(--border);border-radius:8px;font-size:16px}input:focus{outline:2px solid var(--accent);outline-offset:1px}button{min-height:44px;padding:0 18px;border-radius:8px;font-size:15px;font-weight:600;cursor:pointer}.primary{background:var(--accent);color:#fff;border:1px solid var(--accent)}.secondary{background:#fff;color:var(--text);border:1px solid var(--border)}button:disabled{opacity:.6;cursor:default}.error{background:var(--error-bg);color:var(--error);padding:12px;border-radius:8px;font-size:14px}.meta{display:flex;justify-content:space-between;gap:12px;padding-bottom:10px;margin-bottom:12px;border-bottom:1px solid var(--border);font-size:14px;font-weight:500}.code{font:600 26px/1.4 ui-monospace,SF Mono,Menlo,monospace;letter-spacing:4px;text-align:center;background:var(--bg);padding:14px;border-radius:8px;word-break:break-word}