How to install CSS code / stylesheets
Paste the code into a passage with "stylesheet" in the tags box.
Such passages must only contain CSS code.

How to install script code / Javascript code
Paste the code into a passage with "script" in the tags box.
Such passages must only contain Javascript code.

How to center the text of all passages
CSS:
.passage { text-align:center; max-width:50%; margin:auto; } body { margin: 4em; }
Note: 50% can be changed to a different value if you want the text to be wider or narrower.

How to remove the entire Sugarcane sidebar
CSS:
#sidebar { display: none; }
If you're also centering the text, also include this:
#passages ( margin-left: 0; }

How to remove the vertical line to the left of Sugarcane passages
CSS:
#passages { border-left: 0; padding-left: 0; }

How to link to a passage whose name is in a variable
Twine code:
<<print "[[Link text|" + $variable + "]]">>

How to link to a passage inside a HTML block
HTML:
<a href='javascript:void(0)' class='internalLink' onclick='state.display("PassageName")'>Link text</a>
Or, install this script to obviate the need for HTML blocks.

How to <<display>> a passage whose name is in a variable
Twine code:
<<print tale.get($variable).text>>
Or, install this script.

How to change the page title
Twine code:
<<set document.title = "Page title">>
In Sugarcane, this will only remain until you change passages.

How to change the mouse cursor into an image
CSS:
* { cursor: url( imageurl.gif ) 8 8; }
Alter the '8's to be the X and Y pixel coordinates of the cursor's hotspot, measured from the image's top-left corner.
Note: IE, and certain Mac versions of browsers don't support PNG or JPG files.