When building a responsive design, you can choose to set both minimum and maximum dimensions for that design. By setting these minimum and maximum dimensions, you can ensure that your design is never displayed at a size that is either too big or too small for the layout you've created.

To turn on minimum and maximum dimensions for a responsive design, you can click the 'Set Min/Max Dimensions' checkbox in the left corner of the top bar in the 'All Sizes' or 'Active Sizes' views.

Once you have turned on minimum and maximum dimensions, you will be able to provide values for the minimum and maximum width and height of your design. All values are measured in pixels.

If you do not set a minimum value for either dimension, the minimum value will automatically be set to 0. If you do not set a maximum value for either dimension, the design will be allowed to extend infinitely.

Once the minimum and maximum value is set in the top bar, those values will automatically be applied to the minimum and maximum values for the Preview and Export panels.