GptMarkdownStyleSheet class

Per-component appearance, in one object.

Pass it to GptMarkdown(styleSheet: ...) for a single widget, or to GptMarkdownThemeData(styleSheet: ...) for the whole app. Values on the widget win over the theme per field, so a widget that overrides one thing keeps the theme's answer for everything else.

Every field of every style is optional, and anything still unset resolves to the value the package used before it was configurable — so adding a style sheet never changes how existing content looks.

GptMarkdown(
  text,
  styleSheet: const GptMarkdownStyleSheet(
    blockQuote: BlockQuoteStyle(barWidth: 4),
    codeBlock: CodeBlockStyle(showCopyButton: false),
  ),
)

For structure rather than appearance, use the builders — codeBuilder, tableBuilder, blockQuoteBuilder and the rest. The rule across the package is: style object for looks, builder for structure.