Marimekko Data Labels Font Size

Question

I am creating a marimekko chart. My code is as follows:

# Create percentage columns
df['Inside_perc'] = (df['Inside'] / (df['Inside'] + df['Other'] + df['Travel'] + df['Dining'] + df['Gas'])) * 100
df['Other_perc'] = (df['Other'] / (df['Inside'] + df['Other'] + df['Travel'] + df['Dining'] + df['Gas'])) * 100
df['Travel_perc'] = (df['Travel'] / (df['Inside'] + df['Other'] + df['Travel'] + df['Dining'] + df['Gas'])) * 100
df['Dining_perc'] = (df['Dining'] / (df['Inside'] + df['Other'] + df['Travel'] + df['Dining'] + df['Gas'])) * 100
df['Gas_perc'] = (df['Gas'] / (df['Inside'] + df['Other'] + df['Travel'] + df['Dining'] + df['Gas'])) * 100
​
# Create total columnms
​
df['Sum'] = df['Inside'] + df['Other'] + df['Travel'] + df['Dining'] + df['Gas']
​
'''Create data and color lists'''
data = {"Inside": df['Inside_perc'],
        "Other": df['Other_perc'],
        "Travel": df['Travel_perc'],
        "Dining": df['Dining_perc'],
        "Gas": df['Gas_perc']}
​
colors= {"Inside": '#001739',
         "Other": '#D8D8D8',
         "Travel": '#AECEFF',
         "Dining": '#93E7FF',
        'Gas': '#BFBFBF'}
​
​
'''Define horizontal lenghth'''
sum = df['Sum']
widths  = sum
x_width = sum.sum()
​
'''Define labels'''
labels = ['FY19', 'FY20', 'FY21', 'FY22', 'FY23', 'FY24']
​
'''Plot the marimekko'''
​
fig = go.Figure()
for key in data:
    fig.add_trace(go.Bar(name = key,
                     y = data[key],
                     x = np.cumsum(widths) - widths,
                     width = widths, offset = 0,
                     marker = {'color' : colors[key]},
                     customdata = data[key],
                     texttemplate = "%{y:.0f}",
                     textposition = "inside",
                     textangle = 0,textfont_color = "white",
                     textfont_size = 1))
​
    
fig.update_layout(title={'text': "Costco Card Net Sales Category",
                         'xanchor': 'center',
                         'yanchor': 'top'})
​
fig.update_layout(title_text = "M",
                  barmode = "stack", 
                  title_font_size  = 12,legend_font_size = 12, 
                  width = 2000, height = 500)
​
fig.update_xaxes(title_text=
                 'Width of each bar = Net Sales($B)',
                 range = [0, x_width],  
                 title_font_size = 14,                   
                 tickvals = np.cumsum(widths)-widths/2,
                 ticktext =["%s<br>%d"% (l, w) for l,w 
                            in zip(labels, widths)],
                 tickfont = dict(family='Arial', 
                                color='#002D72', size=12))
​
fig.update_yaxes(title_text = 'Percentage (%)',
                 range = [0,100],
                 title_font=dict(size=16,
                                 family='Arial', color='#002D72'))
​
fig.update_layout(
    autosize=False,
    width=1500,
    height=600)
fig.show()

At issue is the font size. The font size changes with the area of rectangle. So when the area is very small the font size becomes very difficult to read. I can't seem to get the font size to be the same regardless of the area. Or remove font size all together.