It depends on what is previewing differently. If it is your alignment, you may want to utilize HTML tables.To make your websites more viewer friendly for all screen sizes, use HTML tables. When you use HTML tables to display your content, you are giving your viewers the option of previewing your websites in an absolute formation (meaning: the content will hold it's position, regardless of screen size).
I am a freelance web designer. If you'd like more help regarding this issue. please contact me. Hope this information was helpful.