body { font-family: system-ui; padding: 20px; background: #0f172a; color: #e2e8f0; }
.container { max-width: 800px; margin: auto; }
textarea { width: 100%; height: 280px; background: #1e293b; color: #e2e8f0; border: 1px solid #334155; border-radius: 8px; padding: 12px; font-family: monospace; }
button { background: #38bdf8; color: #0f172a; border: none; padding: 10px 20px; border-radius: 8px; font-weight: bold; cursor: pointer; margin: 10px 0; }
button:disabled { background: #475569; cursor: not-allowed; }
pre { background: #1e293b; padding: 12px; border-radius: 8px; overflow-x: auto; white-space: pre-wrap; }
.ok { color: #4ade80; } .err { color: #f87171; }