Good work, but let me ask you for small changes to make it superb!
Let talk about good parts first
Layout is functional and responsive, really good, but this could be better for mobile I’ll tell how.
Placeholder for textfield and textarea, very good.
Good sharp submit button, dude I like it so much.
And now some issues
Well the first one is about radio and checkbox buttons, they don’t have any label tag associated, please fix.
first combobox comes without any non selectable option by default (e.g. “please select”), but about the second combobox, you did it well.
One thing I don’t like about the design is the bad contrast between gray and crimson colour, gray is not very visible with very saturated colours like crimson, magenta, etc… please check:
Not all screens(including mine) render it clear. check gray placeholder colour which is not very clear with crimson bgcolor.
I also suggest for mobile you may let combobox goes and fit the container width just like textfields do.
Same I think bringing more size for combobox is good, same for text fields.
Like to see some update and progress with those issues fixed soon.
You may also check my survey form challenge walkthrough article which I stated these notes there too with samples and explanations(feedback is appreciated also)
keep going on great work, happy programming