Windows Classic

Windows Classic refers to the built-in native look and feel of Microsoft Windows, specifically the variation that has been introduced with Windows 95 and further refined in later system verisons. The most recent iteration of the classic theme has been introduced in Windows 2000 and Windows Me. Unlike other visual styles, which are implemented using  resource files, the classic theme is implemented directly in the User API and offers more customizability of various element sizes and colors.

At its peak, Windows 2000 offered 22 different presets for the classic theme, including 4 high contrast accessibility presets and some of which were also available in larger sizes.

Ever since Windows XP introduced a theme engine, which allowed more complex modification to the system's look and feel, the classic theme is no longer used by default in client versions, but it could still be enabled in the Control Panel. Although server versions also included the theme engine, the classic theme was still used as the default theme due to performance reasons up to Windows Server 2008 R2, but Luna can be enabled in Windows Server 2003 by enabling the Themes service, and Windows Aero and Windows Basic in Windows Server 2008 and 2008 R2 can be enabled by installing the Desktop Experience feature in Server Manager and then enabling the Themes service (the same step can be completed in Windows Server 2012 and 2012 R2 to enable the Windows 8.x-like Aero theme, though the Themes service is already enabled by default). Until Windows 8, the classic theme was used to implement high contrast settings.

With the introduction of software rendering in the Desktop Window Manager and the Aero Lite visual style, which also allows modification to a degree similar to the classic theme, it is no longer accessible by the user in Windows 8 and equivalent versions, with Windows Server 2012 switching to Aero Lite and Windows PE using Windows Basic, however, the implementation is still present for compatibility reasons and an application can ask the theme engine to disable theming for its windows, which will force the classic theme.