[BUG] Plain code block unreadable with light profile

[toy]

Describe the bug

Using light Terminal/iTerm profile plain code block is unreadable (dark text on dark background).

Given README.md with following content:

# Test

```ruby
some = :code
```

```
some
text
```

    some
    text

Running cat README.md | python -m rich.markdown -.

Produces:

Platform

Click to expand

Running on macOS 12.3.1 using Terminal 2.12.5

python -m rich.diagnose:

╭───────────────────────── <class 'rich.console.Console'> ─────────────────────────╮
│ A high level console interface.                                                  │
│                                                                                  │
│ ╭──────────────────────────────────────────────────────────────────────────────╮ │
│ │ <console width=97 None>                                                      │ │
│ ╰──────────────────────────────────────────────────────────────────────────────╯ │
│                                                                                  │
│     color_system = None                                                          │
│         encoding = 'utf-8'                                                       │
│             file = <_io.TextIOWrapper name='<stdout>' mode='w' encoding='utf-8'> │
│           height = 42                                                            │
│    is_alt_screen = False                                                         │
│ is_dumb_terminal = False                                                         │
│   is_interactive = False                                                         │
│       is_jupyter = False                                                         │
│      is_terminal = False                                                         │
│   legacy_windows = False                                                         │
│         no_color = False                                                         │
│          options = ConsoleOptions(                                               │
│                        size=ConsoleDimensions(width=97, height=42),              │
│                        legacy_windows=False,                                     │
│                        min_width=1,                                              │
│                        max_width=97,                                             │
│                        is_terminal=False,                                        │
│                        encoding='utf-8',                                         │
│                        max_height=42,                                            │
│                        justify=None,                                             │
│                        overflow=None,                                            │
│                        no_wrap=False,                                            │
│                        highlight=None,                                           │
│                        markup=None,                                              │
│                        height=None                                               │
│                    )                                                             │
│            quiet = False                                                         │
│           record = False                                                         │
│         safe_box = True                                                          │
│             size = ConsoleDimensions(width=97, height=42)                        │
│        soft_wrap = False                                                         │
│           stderr = False                                                         │
│            style = None                                                          │
│         tab_size = 8                                                             │
│            width = 97                                                            │
╰──────────────────────────────────────────────────────────────────────────────────╯
╭─── <class 'rich._windows.WindowsConsoleFeatures'> ────╮
│ Windows features available.                           │
│                                                       │
│ ╭───────────────────────────────────────────────────╮ │
│ │ WindowsConsoleFeatures(vt=False, truecolor=False) │ │
│ ╰───────────────────────────────────────────────────╯ │
│                                                       │
│ truecolor = False                                     │
│        vt = False                                     │
╰───────────────────────────────────────────────────────╯
╭──────── Environment Variables ────────╮
│ {                                     │
│     'TERM': 'xterm-256color',         │
│     'COLORTERM': None,                │
│     'CLICOLOR': '1',                  │
│     'NO_COLOR': None,                 │
│     'TERM_PROGRAM': 'Apple_Terminal', │
│     'COLUMNS': None,                  │
│     'LINES': None,                    │
│     'JPY_PARENT_PID': None,           │
│     'VSCODE_VERBOSE_LOGGING': None    │
│ }                                     │
╰───────────────────────────────────────╯
platform="Darwin"

pip freeze | grep rich:

rich==12.4.1