XSL 1.1 allows transparent to be used with background-color and with the ‘border-*’ properties that set a border color. Antenna House Formatter extends this to allow transparent whereever a color is specified. When color: transparent; is specified for text, space equivalent to the size of the formatted text is left in the output, but the characters are not output. When the characters are to be included in the output but just not visible, use color: rgba(0, 0, 0, 0) instead.