Notebook & Interface Customization
The Wolfram Language has over a thousand options that allow full control over every aspect of its interface. These options can be set interactively from menus, defined in stylesheets, or manipulated programmatically using the Wolfram Language's symbolic programming capabilities.
General Customization Menus
Preferences — set global preferences such as syntax coloring
Option Inspector — all notebook and interface options, settable at various levels
Format ▶ Stylesheet — pick a stylesheet for a notebook
Format ▶ Edit Stylesheet — edit a complete or cascading stylesheet
Evaluation Control »
Evaluation ▶ Notebook's Default Context — localize everything by notebook, cell, ...
Notebook's Kernel — specify the local or remote kernel to use for evaluation
Programmatic Customization »
Options, SetOptions — programmatically find and set all notebook options