Ответ на "What is the best way to prevent keyboard marks?"Check if the little plastic pads on each top side of the screen are still here and not cut. They serve to keep a small distance when the screen is closed. You can increase distance with added thick adhesive tape.You can try to add two thin little pads on bottom of screen too. Check for the needed thickness with the screen closed to keep the hook grabbed on bottom part. Eventually try to adjust the hinge height to increase distance to keyboard. And never put big objects on screen size when you carry the Mac in backpack or use a sheet of hard material (metal, epoxy,..) as separator to avoid any pressure on the top cover.