Horizontal Dendrogram Light Theme

import matplotlib.pyplot as plt
import numpy as np
from scipy.cluster.hierarchy import dendrogram, linkage, set_link_color_palette

np.random.seed(654)

items = ['Alpha', 'Beta', 'Gamma', 'Delta', 'Epsilon', 'Zeta', 'Eta',
         'Theta', 'Iota', 'Kappa', 'Lambda', 'Mu', 'Nu', 'Xi', 'Omicron']

data = np.random.rand(len(items), 5) * 80
Z = linkage(data, method='ward')

fig, ax = plt.subplots(figsize=(10, 9), facecolor='#ffffff')
ax.set_facecolor('#ffffff')

set_link_color_palette(['#F5276C', '#27D3F5', '#6CF527', '#F5B027', '#5314E6'])

dn = dendrogram(Z, labels=items, orientation='right', leaf_font_size=11,
                color_threshold=0.6*max(Z[:,2]), above_threshold_color='#9ca3af', ax=ax)

ax.set_title('Hierarchical Cluster Analysis', fontsize=15, 
             color='#1f2937', fontweight='bold', pad=15)
ax.set_xlabel('Distance', fontsize=11, color='#374151')
ax.set_ylabel('Items', fontsize=11, color='#374151')

ax.tick_params(axis='both', colors='#374151', labelsize=10)
ax.spines['top'].set_visible(False)
ax.spines['right'].set_visible(False)
ax.spines['left'].set_color('#e5e7eb')
ax.spines['bottom'].set_color('#e5e7eb')
ax.xaxis.grid(True, color='#f3f4f6', linewidth=0.5)

plt.tight_layout()
plt.show()