:root{--bg: #0f172a;--card: #1e293b;--border: #334155;--text: #e2e8f0;--muted: #94a3b8;--accent: #6366f1;--accent-hover: #4f46e5;--success: #22c55e;--error: #ef4444;color-scheme:dark}*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--text)}.container{max-width:640px;margin:0 auto;padding:3rem 1.5rem}header h1{margin:0;font-size:1.75rem}.subtitle{color:var(--muted);margin-top:.25rem}.card{background:var(--card);border:1px solid var(--border);border-radius:12px;padding:1.5rem;margin-top:1.5rem}.field{display:flex;flex-direction:column;gap:.4rem;margin-bottom:1.25rem}.field>span{font-size:.85rem;color:var(--muted)}select,textarea{width:100%;padding:.65rem .75rem;background:#0b1220;color:var(--text);border:1px solid var(--border);border-radius:8px;font-size:.95rem;font-family:inherit}textarea{font-family:ui-monospace,SF Mono,Menlo,monospace;resize:vertical}textarea.invalid{border-color:var(--error)}.error-text{color:var(--error)}button{width:100%;padding:.75rem;background:var(--accent);color:#fff;border:none;border-radius:8px;font-size:1rem;font-weight:600;cursor:pointer;transition:background .15s ease}button:hover:not(:disabled){background:var(--accent-hover)}button:disabled{opacity:.5;cursor:not-allowed}pre{background:#0b1220;padding:1rem;border-radius:8px;overflow-x:auto;margin:0}.card.success h2{color:var(--success);margin-top:0}.card.error h2{color:var(--error);margin-top:0}