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

Stylesheets »

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

CurrentValue   ▪ FrontEndExecute   ▪ NotebookEventActions   ▪ ...