def summarize(series, label):
    print(f"\n── {label} ──")
    print(f"  Mean:    {series.mean():>10.2f}")
    print(f"  Median:  {series.median():>10.2f}")
    print(f"  Std Dev: {series.std():>10.2f}")
    print(f"  IQR:     {series.quantile(0.75) - series.quantile(0.25):>10.2f}")
    print(f"  Skew:    {series.skew():>10.3f}")

summarize(df["revenue_usd"],     "Revenue (USD)")
summarize(df["units_sold"],      "Units Sold")
summarize(df["return_rate_pct"], "Return Rate (%)")