Use ‘|’ symbol to author title for icon buttons. It works only for icon buttons.

A button’s background color can be set by writing the button text followed by the color in {} braces, where the value can be a predefined name like 'orange', 'white', 'pink', 'blue', 'green', 'red', 'gizmos', or any valid CSS color such as a hex code (#ff0000) or other CSS color formats (e.g., white, black);

The button text color is not customizable and is always black, and on hover all buttons change to a black background with white text.