A line graph styled with a dark background and neon glowing lines in the style of Cyberpunk.

1 - The Basis#

Let’s make up some numbers, put them in a Pandas dataframe and plot them:

import pandas as pd
import matplotlib.pyplot as plt

df = pd.DataFrame({'A': [1, 3, 9, 5, 2, 1, 1],
                   'B': [4, 5, 5, 7, 9, 8, 6]})

df.plot(marker='o')
plt.show()

A simple chart consisted of two lines, one blue line, and one orange line. The lines are on a white background.

2 - The Darkness#

Not bad, but somewhat ordinary. Let’s customize it by using Seaborn’s dark style, as well as changing background and font colors:

plt.style.use("seaborn-dark")

for param in ['figure.facecolor', 'axes.facecolor', 'savefig.facecolor']:
    plt.rcParams[param] = '#212946'  # bluish dark grey

for param in ['text.color', 'axes.labelcolor', 'xtick.color', 'ytick.color']:
    plt.rcParams[param] = '0.9'  # very light grey

ax.grid(color='#2A3459')  # bluish dark grey, but slightly lighter than background

A simple chart with a dark background consisted of two lines: A is the blue line and B is the orange line.

3 - The Light#

It looks more interesting now, but we need our colors to shine more against the dark background:

fig, ax = plt.subplots()
colors = [
    '#08F7FE',  # teal/cyan
    '#FE53BB',  # pink
    '#F5D300',  # yellow
    '#00ff41', # matrix green
]
df.plot(marker='o', ax=ax, color=colors)

A simple chart with a dark background consisted of two lines: A is the blue line and B is the purple line.

4 - The Glow#

Now, how to get that neon look? To make it shine, we redraw the lines multiple times, with low alpha value and slightly increasing linewidth. The overlap creates the glow effect.

n_lines = 10
diff_linewidth = 1.05
alpha_value = 0.03

for n in range(1, n_lines+1):

    df.plot(marker='o',
            linewidth=2+(diff_linewidth*n),
            alpha=alpha_value,
            legend=False,
            ax=ax,
            color=colors)

A simple chart with a dark background consisted of two lines: A is the blue line and B is the purple line. However, they have a neon look and are both glowing.

5 - The Finish#

For some more fine tuning, we color the area below the line (via ax.fill_between) and adjust the axis limits.

Here’s the full code:

import pandas as pd
import matplotlib.pyplot as plt


plt.style.use("dark_background")

for param in ['text.color', 'axes.labelcolor', 'xtick.color', 'ytick.color']:
    plt.rcParams[param] = '0.9'  # very light grey

for param in ['figure.facecolor', 'axes.facecolor', 'savefig.facecolor']:
    plt.rcParams[param] = '#212946'  # bluish dark grey

colors = [
    '#08F7FE',  # teal/cyan
    '#FE53BB',  # pink
    '#F5D300',  # yellow
    '#00ff41',  # matrix green
]


df = pd.DataFrame({'A': [1, 3, 9, 5, 2, 1, 1],
                   'B': [4, 5, 5, 7, 9, 8, 6]})

fig, ax = plt.subplots()

df.plot(marker='o', color=colors, ax=ax)

# Redraw the data with low alpha and slightly increased linewidth:
n_shades = 10
diff_linewidth = 1.05
alpha_value = 0.3 / n_shades

for n in range(1, n_shades+1):

    df.plot(marker='o',
            linewidth=2+(diff_linewidth*n),
            alpha=alpha_value,
            legend=False,
            ax=ax,
            color=colors)

# Color the areas below the lines:
for column, color in zip(df, colors):
    ax.fill_between(x=df.index,
                    y1=df[column].values,
                    y2=[0] * len(df),
                    color=color,
                    alpha=0.1)

ax.grid(color='#2A3459')

ax.set_xlim([ax.get_xlim()[0] - 0.2, ax.get_xlim()[1] + 0.2])  # to not have the markers cut off
ax.set_ylim(0)

plt.show()

A simple chart with a dark background consisted of two lines: A is the blue line and B is the purple line. However they are neon, both glow, and the area below them glows as well.

If this helps you or if you have constructive criticism, I’d be happy to hear about it! Please contact me via here or here. Thanks!