responsive page using css and html

What are you most proud of, and what would you do differently next time?

this was quite easy

What challenges did you encounter, and how did you overcome them?

but i am beginning to notice a flaw in my designs, they go out of place whenever i resize my browser, what causes that?

What specific areas of your project would you like help with?

how do i make my over all design static? so that no matter how any webpage gets resized, my contents doesn't get out of place.