Multi-Series Stairs

import matplotlib.pyplot as plt
import numpy as np

COLORS = {
    'a': '#6366F1',
    'b': '#10B981',
    'c': '#F59E0B',
    'background': '#FFFFFF',
    'text': '#1E293B',
    'text_muted': '#64748B',
    'grid': '#F1F5F9'
}

edges = np.arange(13)
y_a = [2, 3, 4, 5, 4, 5, 6, 7, 6, 7, 8, 9]
y_b = [1, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 8]
y_c = [3, 4, 3, 4, 3, 4, 5, 4, 5, 6, 5, 6]

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

series = [(y_a, COLORS['a'], 'Product A'), (y_b, COLORS['b'], 'Product B'), (y_c, COLORS['c'], 'Product C')]

for y, color, label in series:
    ax.stairs(y, edges, linewidth=2.5, color=color, label=label)
    ax.scatter([11.5], [y[-1]], s=60, c=color, edgecolors='white', linewidths=2, zorder=4)
    ax.text(12.2, y[-1], f'{y[-1]}', fontsize=10, color=color, fontweight='bold', va='center')

ax.spines['top'].set_visible(False)
ax.spines['right'].set_visible(False)
ax.spines['left'].set_color(COLORS['grid'])
ax.spines['bottom'].set_color(COLORS['grid'])
ax.yaxis.grid(True, color=COLORS['grid'], linewidth=1, zorder=0)
ax.set_axisbelow(True)
ax.tick_params(axis='both', colors=COLORS['text_muted'], labelsize=9, length=0, pad=8)
ax.set_xlim(0, 14)
ax.set_ylim(0, 11)
ax.set_xlabel('Month', fontsize=10, color=COLORS['text'], labelpad=10)
ax.set_ylabel('Sales (K)', fontsize=10, color=COLORS['text'], labelpad=10)
ax.legend(loc='upper center', bbox_to_anchor=(0.5, -0.12), ncol=3, frameon=False, fontsize=10, labelcolor=COLORS['text_muted'])

plt.tight_layout()
plt.show()