f7723559_CSS_HTML_XHTML_Reference_Book__Description_and_notes
[Property/Values] left either a length, percentage, auto, or inherit [Description and notes] 
for setting the distance that an element should be offset from its parent element's left edge initial value: auto; may only be applied to positioned elements; not inherited; percentages refer to width of containing block
CSS HTML XHTML Reference Book
Description and notes