A UX Designer wants to use the Salesforce Lightning Design System (SLDS) to create consistent...

 The Salesforce Lightning Design System (SLDS) is a collection of design resources that help create consistent and beautiful user interfaces across various platforms. The SLDS includes base components, tokens, design patterns, icons, fonts, and more, that follow the design principles and best practices of Lightning Experience. The SLDS can be used on the following three platforms:

Visualforce: Visualforce is a framework that allows developers to create custom user interfaces for web and mobile applications on the Salesforce platform. Visualforce pages can leverage the SLDS styles to match the look and feel of Lightning Experience, without writing any CSS code. By adding the attribute lightningStylesheets="true" to the  tag, Visualforce pages can automatically transform the standard Visualforce components into their SLDS equivalents12.

Heroku: Heroku is a cloud platform that supports various languages and frameworks, such as Node.js, Java, or PHP. Heroku applications can leverage the SLDS resources, such as the base components, the tokens, and the design patterns, to create web applications that have a consistent Lightning Experience look and feel. Heroku applications can also use the Lightning Out feature to embed Lightning components into their pages, and use the Lightning Web Components framework to create reusable UI elements34.

Azure: Azure is a cloud platform that offers various services and tools for building, deploying, and managing applications. Azure applications can leverage the SLDS resources, such as the base components, the tokens, and the design patterns, to create web applications that have a consistent Lightning Experience look and feel. Azure applications can also use the Lightning Out feature to embed Lightning components into their pages, and use the Lightning Web Components framework to create reusable UI elements56.