Use pprint

import pprint

x  = {
  'planet' : {
    'name' : 'Earth',
    'has' : {
      'plants' : 'yes',
      'animals' : 'yes',
      'cryptonite' : 'no'
    }
  }
}
pp = pprint.PrettyPrinter(indent=4)
pp.pprint(x)

This outputs

{   'planet': {   'has': {   'animals': 'yes',
                             'cryptonite': 'no',
                             'plants': 'yes'},
                  'name': 'Earth'}}

Play around with pprint formatting and you can get the desired result.

• http://docs.python.org/library/pprint.html

Using built-in vim features:

In a terminal: pip install autopep8
Then, in vim: au FileType python setlocal formatprg=autopep8\ -, then select your dictionary and gq.

Using a plugin: check out https://github.com/Chiel92/vim-autoformat. That's one of many plugins that can automatically format code for you.

I'm not sure how exactly you want the formatting to look like, but you could start with a function like this:

def pretty(d, indent=0):
   for key, value in d.items():
      print('\t' * indent + str(key))
      if isinstance(value, dict):
         pretty(value, indent+1)
      else:
         print('\t' * (indent+1) + str(value))

Indeed you cannot affect the display of the Python output with CSS, but you can give your results to a formatting function that will take care of making it "beautiful". In your case, you could use something like this:

def compare_dicts(dict1, dict2, col_width):
    print('{' + ' ' * (col_width-1) + '{')
    for k1, v1 in dict1.items():
        col1 = u"  %s: %.3f," % (k1, v1)
        padding = u' ' * (col_width - len(col1))
        line = col1 + padding
        if k1 in dict2:
            line = u"%s  %s: %.3f," % (line, k1, dict2[k1])
        print(line)
    print('}' + ' ' * (col_width-1) + '}')

dict1 = {
    'foo': 0.43657,
    'foobar': 1e6,
    'bar': 0,
}


dict2 = {
    'bar': 1,
    'foo': 0.43657,
}

compare_dicts(dict1, dict2, 25)

This gives:

{                        {
  foobar: 1000000.000,   
  foo: 0.437,              foo: 0.437,
  bar: 0.000,              bar: 1.000,
}                        }