Rebuild one section by hand

Pick the smallest section of your page. The footer, or the header. Not the hero.

Copy the whole file to backup.html so nothing is at risk. Then delete that section from the original and write it again yourself.

It will be slow and it will look worse. Both are expected and neither is the measurement.

When you are stuck, look at the backup, read the line and make sure you understand it. Then close the backup and type your own version. Copying may finish the section faster, but it does not tell you whether you understood it.

When it works, compare the two. Yours is probably shorter. It may well be more semantic, because you are thinking about what the thing is rather than producing the average of everything.

Then write three sentences in your repo: what was harder than expected, what was easier, and what you want to learn next. That last sentence gives you a useful direction for the next piece of work.