body { font-family: Arial,sans-serif; padding:20px; background:#f6f8fa; color:#222; }
.container { max-width:900px; margin:0 auto; background:#fff; padding:20px; border-radius:8px; }
pre { background:#0b1220; color:#e6fbff; padding:10px; border-radius:6px; overflow:auto; max-height:240px; }
button { padding:6px 12px; margin:6px 0; }
input { padding:6px; margin-right:6px; }