How to align 9 blocks in one 100%?

Question

css

1. It is necessary that they go 3 in a row.
2. When the screen was enlarged or reduced, they did not move apart.
3. What would the right and left pressed against the sides.
4. What would be equal indentation from the central ones and from above and below

I drew it as best I could.
Browsers are new. I've been suffering for two days now.

Answer 1

jsfiddle.net/rrftmyoe try this. If you need a fix. width, change the width: 100% value of the .w100 class to whatever you want.

Answer 2

And how to add an adaptive height to these blocks?

Answer 3

and bootstrap is not suitable?