property whose value determines the presentation (e.g. font, color, size, location, padding, volume, synthesized speech prosody) of content elements as they are rendered (e.g. onscreen, via loudspeaker, via braille display) by user agents

Style properties can have several origins:

• User agent default styles: The default style property values applied in the absence of any author or user styles. Some web content technologies specify a default rendering, others do not;
• Author styles: Style property values that are set by the author as part of the content (e.g. in-line styles, author style sheets);
• User styles: Style property values that are set by the user (e.g. via user agent interface settings, user style sheets)