- Design is a skill you can learn but you need to put at least a few days or weeks into it to make some progress. A lot of people who say they can't design have barely spent a few hours working on their own designs or following tutorials. For example, I don't think anybody would say "I'm not good at Java" without trying to learn it first but people do this with design all the time without giving themselves a fair chance to try.
- Don't design and code at the same time. You'll waste time and burn yourself out getting lost in CSS rabbit holes, trying to make the code look pretty etc. and then when you get it working it and you step back to look at it, you realise the design doesn't work and it needs more iterations. Design a mockup first in something like Figma or InVision and only start coding when the design is ready. You can iterate on the design an order of magnitude faster this way because you can just drag/drop things around instead of fighting with how to align and style things in CSS.
Generally once I have an initial rough design drawn in a design tool, I duplicate the whole thing, tweak it (like changing the colors, sizes, fonts), duplicate that, tweak it etc. to explore and combine lots of different design ideas until I happen upon some combination I like. It's hard to replicate this process and avoid tunnel vision when you're designing in an IDE instead.