Symmetric Stackplot

import matplotlib.pyplot as plt
import numpy as np

COLORS = {
    'layers': ['#6366F1', '#8B5CF6', '#A855F7', '#C084FC', '#E879F9'],
    'background': '#FFFFFF',
    'text': '#1E293B',
    'text_muted': '#64748B',
    'grid': '#F1F5F9'
}

x = np.linspace(0, 10, 100)
y1 = 2 + np.sin(x)
y2 = 1.5 + 0.5*np.sin(x + 1)
y3 = 1 + 0.3*np.sin(x + 2)
y4 = 0.8 + 0.2*np.sin(x + 3)
y5 = 0.5 + 0.1*np.sin(x + 4)

fig, ax = plt.subplots(figsize=(10, 6), dpi=100)
ax.set_facecolor(COLORS['background'])
fig.patch.set_facecolor(COLORS['background'])

ax.stackplot(x, y1, y2, y3, y4, y5, colors=COLORS['layers'], alpha=0.85, baseline='wiggle',
             labels=['Layer 1', 'Layer 2', 'Layer 3', 'Layer 4', 'Layer 5'])

ax.axhline(0, color=COLORS['text'], linewidth=0.5)
ax.spines['top'].set_visible(False)
ax.spines['right'].set_visible(False)
ax.spines['left'].set_color(COLORS['grid'])
ax.spines['bottom'].set_visible(False)
ax.tick_params(axis='both', colors=COLORS['text_muted'], labelsize=9, length=0, pad=8)
ax.set_xlim(0, 10)
ax.legend(loc='upper center', bbox_to_anchor=(0.5, -0.10), ncol=5, frameon=False, fontsize=8, labelcolor=COLORS['text_muted'])

plt.tight_layout()
plt.show()