Function apply_markup_declaration 

pub fn apply_markup_declaration(
    name: &str,
    value: &str,
    attrs: &mut Attributes,
) -> Result<bool, ParseError>

Give an element a style as its markup would: the value lands in attrs, and the declaration joins Attributes::markup_styles under the spelling the cascade files it under.

For the boxes a compiler builds itself (the parts of a <dropdown> or a <menu>, a page’s gate) rather than ones an author wrote. The record is what a restyle rebuilds an element’s markup tier from, so a value written into an Attributes field alone is gone the first time a class, a theme or a breakpoint re-resolves the element. Returns what apply_inline_declaration returns; nothing is recorded unless the declaration applied.