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I struggled to get the blue background colour the same as in the screenshots provided. Is there a way to get the RGB/Hex values from a specific part of an image, or is that not possible?

I'm not super familiar with semantics for html, so please could you suggest what elements I could have used instead of divs.

I would also like to know, generally speaking, when it is more appropriate to use % values (or other relative values) instead of px values when working with sizing, margin, padding, etc.

I would also appreciate any other general feedback :)