Macro css 

macro_rules! css {
    ( $( class : $class_val:expr ),+ $(,)? ) => { ... };
    ( $( style : $style_val:expr ),+ $(,)? ) => { ... };
    ( $( id : $id_val:expr ),+ $(,)? ) => { ... };
    ( class : $class_val:expr, style : $style_val:expr $(,)? ) => { ... };
    ( style : $style_val:expr, class : $class_val:expr $(,)? ) => { ... };
    ( class : $class_val:expr, id : $id_val:expr $(,)? ) => { ... };
    ( id : $id_val:expr, class : $class_val:expr $(,)? ) => { ... };
    ( style : $style_val:expr, id : $id_val:expr $(,)? ) => { ... };
    ( id : $id_val:expr, style : $style_val:expr $(,)? ) => { ... };
    ( class : $class_val:expr, style : $style_val:expr, id : $id_val:expr $(,)? ) => { ... };
    ( class : $class_val:expr, id : $id_val:expr, style : $style_val:expr $(,)? ) => { ... };
    ( style : $style_val:expr, class : $class_val:expr, id : $id_val:expr $(,)? ) => { ... };
    ( style : $style_val:expr, id : $id_val:expr, class : $class_val:expr $(,)? ) => { ... };
    ( id : $id_val:expr, class : $class_val:expr, style : $style_val:expr $(,)? ) => { ... };
    ( id : $id_val:expr, style : $style_val:expr, class : $class_val:expr $(,)? ) => { ... };
    ( $( $key:ident : $val:expr ),+ $(,)? ) => { ... };
}

A StyleAttr struct with either the class, style, id or any combination of fields set. This macro allows for flexible creation of style attributes for SVG elements. It supports various combinations of class, style, and id attributes, making it easy to define the styling of SVG elements in a concise manner.