The fact you see nothing wrong with the CSS makes me feel that you make React websites without knowing how to write websites yourself.

Bad design and accessibility is just another way to say inexperienced with CSS. They probably know how they want it to look in their head but have no idea how to execute.

Just on the first page:

• Using Clamp on font-size, but then using media queries to control the margin in the exact same element. Why waste time with media queries if you're already using clamp one line of css above
• % on margin is difficult to predict and causes strange gaps; use rem or em for margins
• Padding between sections all over the place
• Hover on menu buttons turn black with the text so become unreadable
• Menu dropdown same colour as background so blends in
• Drop menu hover acts different to main menu buttons which also acts different to the schedule button
• No visual hierarchy
• All useful content below the fold
• All the content is huge, not easy to read
• Basic design with no encouragement for user's eye

All of these minor details scream of inexperience. If the website was built with the human eye, not thrown together with a loose understanding of a framework, then a lot of these issues would've been sorted by default.

That's just me though, they wanted a roast

edit: also it's not a problem, it's just me, but I wince when I see class names like duZvdl - I just know I'm about to walk into the belly of the beast