如何在matplotlib中突出显示多条曲线中最低的一条曲线(包络)

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 10, 100)
y1 = np.sin(x)
y2 = np.cos(x)
y3 = np.exp(-x/5)

plt.plot(x, y1, label='Curve 1')
plt.plot(x, y2, label='Curve 2')
plt.plot(x, y3, label='Curve 3')

min_y = np.min([y1, y2, y3], axis=0)

plt.fill_between(x, min_y, np.min([y1, y2, y3], axis=0), color='gray', alpha=0.3)

plt.legend()
plt.xlabel('X')
plt.ylabel('Y')

plt.show()