Examine the plugin's main source files, such as autoload/markdown preview.vim or rplugin/python3, to understand how browser windows are currently opened. The request is to enable split screen opening on macOS, which may require using AppleScript or the 'open' command with specific arguments. Review the issue comments for any additional details or suggestions from users. Consider implementing a macOS specific handler that checks the current window state and opens a new browser window in split screen mode.
