Continuous Error Band

import matplotlib.pyplot as plt
import numpy as np

# === STYLE CONFIG ===
COLORS = {
    'line': '#EC4899',
    'band': '#EC4899',
    'background': '#FAFBFC',
    'text': '#1E293B',
    'text_muted': '#64748B',
    'grid': '#E2E8F0',
}

# === DATA ===
x = np.linspace(0, 10, 50)
y = 3 + 2 * np.sin(x)
error = 0.3 + 0.2 * np.abs(np.sin(x * 2))

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

# === PLOT ===
# Error band
ax.fill_between(x, y - error, y + error, color=COLORS['band'], alpha=0.2)

# Main line
ax.plot(x, y, color=COLORS['line'], linewidth=2.5)

# Sample points with error bars
sample_idx = [0, 12, 25, 37, 49]
ax.errorbar(x[sample_idx], y[sample_idx], yerr=error[sample_idx],
            fmt='o', color=COLORS['line'], ecolor=COLORS['line'],
            elinewidth=2, capsize=5, capthick=2, markersize=8,
            markeredgecolor='white', markeredgewidth=2, zorder=5)

# === AXES ===
ax.set_xlim(0, 10)
ax.set_ylim(0, 6)
ax.set_xlabel('X', fontsize=10, color=COLORS['text_muted'], labelpad=10)
ax.set_ylabel('Y', fontsize=10, color=COLORS['text_muted'], labelpad=10)

# === STYLING ===
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=0.5, alpha=0.7)
ax.set_axisbelow(True)
ax.tick_params(axis='both', colors=COLORS['text_muted'], labelsize=9, length=0, pad=8)

plt.tight_layout()
plt.show()