How do I level all my content? : This is my first post on the site, I'm still learning some basics.
So I found some html/CSS exercises online and tried to copy them and so far so good but I can't level all my content and I'm not sure what to do
[This is the original][1]
and [this is what I have][2]


the menus and last posts are not on the same level as the articles. Why and how to fix it?
I tried playing around with clear and padding and margins..etc..nothing
[This is my CSS][3]


this is the html([1][4]and 
[2][5])


  [1]: https://i.stack.imgur.com/RzcnL.png
  [2]: https://i.stack.imgur.com/0eKDr.png
  [3]: https://i.stack.imgur.com/pXEJ8.png
  [4]: https://i.stack.imgur.com/zOI88.png
  [5]: https://i.stack.imgur.com/qCDvX.png

TIA