Screen Width: px (this is done by JavaScript - the only effect of the JavaScript is to display the width of the window; it has no effect on the size of the blue boxes
Box 1 - Default Settings
Box 3 - Width: 50% with min-width of 400 and max-width of 600

Screen resolution/window > 1200: width of 50% is greater than the max-width of 600, so no change in box size as screen resolution/window changes

Screen resolution/window between 800 and 1200: width of 50% is less than the max-width of 600 and greater than the min-width of 400, so box size changes as screen resolution/window changes

Screen resolution below 800: width of 50% is less than the min-width of 400, so no change in box size as screen resolution/window changes

Revised: February 2, 2021