Highlight

Highlighted text draws attention to key words or phrases with a colored background, similar to a marker pen on paper.

Basic syntax

Photosynthesis converts ==light energy== into chemical energy stored in glucose.

Photosynthesis converts light energy into chemical energy stored in glucose.

→ "light energy" appears with a yellow background highlight.

Multiple highlights can appear in the same sentence:

The ==most important== part of any routing algorithm is ==path normalization==.

The most important part of any routing algorithm is path normalization.

→ Each phrase receives an independent highlight background.

Highlights work alongside other inline extensions in the same sentence:

The ==recommended== command is ::copy[sarde build --minify].

The recommended command is sarde build --minify.

→ "recommended" is highlighted while the command renders as a copyable snippet.

Highlights also work inside block extensions such as asides:

:::tip
You can use ==highlighted text== and `inline code` inside callout blocks.
:::

→ The highlighted phrase renders with the yellow background inside the green tip callout.

Content between == markers is plain text. Markdown formatting (bold, italic, links, code spans) inside a highlight renders as literal characters, not formatted output.
Highlights are single-line only. An opening == on one line cannot be closed on the next. Unmatched markers render as literal == text.
Empty highlights (====) are not parsed. At least one character must appear between the markers.
No attributes or parameters are supported. The syntax is always ==text==.
There is no escaping mechanism for literal == inside highlighted text.
In dark mode, the background shifts to an amber tone with lighter text for contrast.