all: allow combination of default and custom stylesheet

To combine default stylesheet with custom CSS, set the value to "default"
and the file name of custom CSS, separated by comma.
This is the recommended way to use custom stylesheet since it can be set
only on specific pages.

----
// In asciidoctor:
:stylesheet: default, custom.css

// In markdown:
stylesheet: default, custom.css
----

To disable default stylesheet and only using custom CSS, set the value only
to the file name of custom CSS.

Another way to use custom stylesheet is by creating your own template and
pass it to `serve` or `convert` command.
This method makes the stylesheet applied to all pages.

1 files changed, 47 insertions, 0 deletions

diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index 3dc678f..e5d21fe 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -23,6 +23,53 @@ template, we need to restart the "ciigo serve" command.
 Using memfs make us easy to update and see the changes directly, without
 restarting the server.
 
+**🌼 all: improve the default stylesheet and template**
+
+Add common styles for asciidoctor elements with dark theme.
+Common styles including title, header, anchor, lists, table, and footer.
+
+The foreground color changes to conform with color-contrast
+ratio threshold, with score AAA. [1]
+
+Add ARIA role to each section of pages: banner for topbar,
+main for page, and contentinfo for footer.
+This is to make the webpage more robust and functional no matter
+what screen reader technology is used. [2]
+
+For touch devices, increase the line height on Table of Contents.
+This is to help users who may have difficulty in confidently targeting or
+operating small controls. [3]
+
+In the default template, instead of splitting the topbar into top-heading
+and menu, breaking it down by class item.
+
+[1]: https://dequeuniversity.com/rules/axe/4.11/color-contrast +
+[2]: https://dequeuniversity.com/rules/axe/4.11/landmark-one-main +
+[3]: https://dequeuniversity.com/rules/axe/4.11/target-size
+
+
+**🌱 all: allow combination of default and custom stylesheet**
+
+To combine default stylesheet with custom CSS, set the value to "default"
+and the file name of custom CSS, separated by comma.
+This is the recommended way to use custom stylesheet since it can be set
+only on specific pages.
+
+----
+// In asciidoctor:
+:stylesheet: default, custom.css
+
+// In markdown:
+stylesheet: default, custom.css
+----
+
+To disable default stylesheet and only using custom CSS, set the value only
+to the file name of custom CSS.
+
+Another way to use custom stylesheet is by creating your own template and
+pass it to `serve` or `convert` command.
+This method makes the stylesheet applied to all pages.
+
 
 [#v0_15_3]
 ==  ciigo v0.15.3 (2025-12-27)