html = df.style
         .set_properties(**{'width': 200, 'background-color': '#eae2d5',
                            'color': 'black', 'font-size': '14px',
                            'text-align': 'left'},
                         subset=['var1'])
         .set_properties(**{'color': '33[1m'},  # BOLDING rows 1
                         subset=['var1'][0])   # Here is the error.    .
         .set_properties(**{'color': '33[1m'},  # BOLDING rows 7
                         subset=['var1'][7])   # Here is the error.
         .set_properties(**{'width': 80, 'background-color': '#eae2d5',
                            'color': 'black', 'font-size': '14px',
                            'text-align': 'center'},
                         subset=['var3', 'var4'])
         .set_table_styles([{'selector': 'thead',
                             'props': [('background-color', '#b2361e'),
                                       ('color', 'white'),
                                       ('font-size', '18px')]}, ])
         .highlight_null(null_color='white').hide_index().render()

import pandas as pd
ej = [1,2,3,4,5,3,3,4,2,3,4,23,56]
df = pd.DataFrame(dict(var1=ej, var2=ej, var3=ej, var4=ej))

html = (df.style
         .set_properties(**{'width': "200px", 'background-color': '#eae2d5',
                            'color': 'black', 'font-size': '14px',
                            'text-align': 'left'},
                         subset="var1")
         .set_properties(**{'font-weight': "bold"},
                         subset=(0, 'var1'))
         .set_properties(**{'font-weight': 'bold'},
                         subset=(7, 'var1'))
         .set_properties(**{'width': "80px", 'background-color': '#eae2d5',
                            'color': 'black', 'font-size': '14px',
                            'text-align': 'center'},
                         subset=['var3','var4'])
         .set_table_styles([{'selector': 'thead',
                             'props': [('background-color', '#b2361e'),
                                       ('color', 'white'),
                                       ('font-size', '18px')]}, ])
         .highlight_null(null_color='white').hide_index().render()
       )

from IPython.display import HTML
HTML(html)