CSE HTML Validator

i am a beginner on using CSS...
why is that my output on my design on desktop computer becomes not good and in the right position when i tried to run it on my brother's laptop?

is there anything i can about this matter?
i mean how am i suppose to do a design that will perfectly display on both desktop and laptop without any changes on the output?

Please submit the URL of a page that has this problem so people can take a look at the source.

Hi cdan18po:

I have a similar issue with a floating textbox I'm using on my website: http://homemortgageontario.ca

It is the "Our Best Mortgage Rates" table in the header and you'll notice that it fits nicely while viewing on a desktop/laptop, however when on a mobile device (no mobile theme installed on my WP site) the last line does not show up inside the box, it overlaps the bottom of the border.

You'll also notice the last line does not line up appropriately. Can't figure it out for the life of me. I thought because I have a radius on the corner of my border that it is messing with the alignment of the text? Hmmm.

Thanks in advance!