Mailchimp - Project HTML Forms

Hello, I worked on the HTML forms task, and I attempted to create the Mailchimp signup form https://login.mailchimp.com/signup/. I still need to make some changes, such as the border color change on the input form, hyperlinks in terms and conditions, etc.

I used flex for one attempt

I used float for image for the other

I have trouble with positioning things in CSS. My approach at the moment is using trial and error, until I manage to make things look as I want to, but in the end I make so many modifications that I no longer remember which one worked and why. Are there any ways to improve this?

I would appreciate some feedback on what I did (layout, positioning), maybe I over complicated things, and I could have used less changes in CSS.

I just noticed that they look better in full page view, so I will need to create media queries for the page if I will be capable.