I am wondering how the styles.html() partial can be disabled since the doc says
https://pandoc.org/MANUAL.html#variables-for-html

document-css:
Enables inclusion of most of the CSS in the styles.html partial (have a look with pandoc --print-default-data-file=templates/styles.html). Unless you use --css, this variable is set to true by default. You can disable it with e.g. pandoc -M document-css=false

When I look at the default template: 
https://github.com/jgm/pandoc-templates/blob/b5f9ac0d0ec74abfaf7bdbc27ee0bee11391d0ee/default.html5#L18

I cannot recognize any conditional that this styles.html() is not included...
How does that work ? Or is the Doc outdated?

BR Gabriel