The WebFormDefaultStyleScripts setting is a list of string values, representing style or script elements to be added to all landing pages containing web form assets.
The setting’s Values property consists of a toolbar and a list.
•Toolbar: exposing two options:
o Add: clicking this button adds a new value to the bottom of the list. The new value’s default text is ‘New String Value’ (if this value already exists, an incrementable integer is added to ensure uniqueness).
o Remove: clicking the button removes the currently-selected value from the list.
o List: each entry must utilize the same format as the web form asset's Style and script HTML elements property, e.g.:
<link href="http://sitename.com/Publish/CustomScripts/customstyles.css/>" rel="stylesheet" type="text/css" />