This is a professional WordPress theme?

Hi,
I am trying to customize this template, and it turns out somebody has written some CSS code right into HTML in direct style attribute. How am I supposed to change those values? First of all, who thought that a black text would be visible on a dark background?

I thought that I was purchasing a professionally made website design. And when I use development tools to inspect elements I need to change, I see this monstrosity above. Who genuinely thought that a dark color will be visible on a dark color? Who thought that using HTML style attribute for CSS is a good idea?

Not to mention that the marquee running accross the header bar prevents from using the search bar. It can only be clicked when there is no text.

I’d like to know if this could be fixed. Please, fix it. Not only it creates mess when using custom CSS, but it also breaks the website function. I do not have resources to fix these issues myself.