Is there any way to change the text size (font size) of specific blocks when you using asciidoc?

You mention lists and tables... About lists, it can't be done as stated in AsciiDoctor Documentation:

Unsupported Complex AsciiDoc markup is not permitted in attribute values, such as:

  • lists

  • multiple paragraphs

  • other whitespace-dependent markup types

As you can see, there it mentions multiple paragraphs, so while @EhmKah answer is a correct way to set a custom styling block, it won't be rendered as expected in a table/list as it's multi-paragraph.

The Built-in CSS class syntax is the way to go [small]#any phrases# But in order to make this work in a table, you must set the cell type with a specifier in this case, the AsciiDoc specifier denoted by a This means the cell (or column) will render supported AsciiDoc statements, attributes, etc.

Here's a working example:

[frame="none",grid="none"]
|====
a| image::images\logo.png[] a|[.small]#Autor: {author}#
|====

If you have tons of rows/columns, you don't have to manually apply the a to all of them. You can set the columns you need this behavior this way:

[cols="1a,2a",frame="none",grid="none"]
|====
| image::images\logo.png[] |[.small]#Autor: {author}#
|====

You can check its documentation for more about Column Formatting and you can check the Rendered table with variable widths and alignments sub section for more about AsciiDoc (a) and other specifiers.


docinfo.html + --attribute docinfo=shared

You can drop your CSS modifications into a file called docinfo.html:

<style>
/* Your custom CSS. */
</style>

and then build with:

asciidoctor --attribute docinfo=shared README.adoc

and that makes Asciidoctor 2.0.10 place docinfo.html at the bottom of the <head> element.

So you can override most of the default Asciidoctor style from there.

Then it's just a matter of understanding the generated HTML and previous style definitions to override them.

For image specifically, see also: How to set a custom image height for an image in Asciidoctor?