Yep, that's because it's 960px in CSS pixels, which are at 96dpi. Your monitor also has it's own physical dpi so you can't just measure the length of a line on

Yep, that's because it's 960px in CSS pixels, which are at 96dpi. Your monitor also has it's own physical dpi so you can't just measure the length of a line on the screen to infer the OS's dpi.