:root { color-scheme: dark; font-family: Arial, Helvetica, sans-serif; } body { margin: 0; background: #111827; color: #f9fafb; } .container { max-width: 900px; margin: 0 auto; padding: 24px; } .card { background: #1f2937; border: 1px solid #374151; border-radius: 12px; padding: 20px; } .actions { display: flex; gap: 12px; margin-bottom: 16px; } button { border: 0; border-radius: 8px; padding: 10px 16px; cursor: pointer; font-size: 16px; } button:disabled { opacity: 0.6; cursor: default; } pre { background: #0b1220; border: 1px solid #374151; border-radius: 8px; padding: 12px; white-space: pre-wrap; }