Change record status: 
Project: 
Introduced in branch: 
8.x
Introduced in version: 
8.0
Description: 

Most Drupal core themes only worked well for desktop-sized viewports, using hardcoded pixel values in layout CSS and in some cases assuming a significant amount of horizontal space in navigational element design. All core themes have been converted to be responsive and adapt to different screen sizes nicely.

(FYI a backport of the responsive Bartik theme to Drupal 7 can be found at https://drupal.org/project/responsive_bartik)

Impacts: 
Site builders, administrators, editors
Themers