Edit: Added a comment and updated the option bar to match the navbar.
Sure, here you go! I've never done anything like this before so it's probably a formatting disaster, but I've done my best to clean it a bit and add some comments about what does what here. This is what I've come up with after a few hours of just poking around with the inspect element feature and reading some tutorials:
/* The little arrow button in the bottom right that takes you back to the top of the page */ #scroll-top {
background: linear-gradient(to top right, rgba(229, 0, 32, .8) , rgba(242, 151, 57, .8));
box-shadow: 0px 4px 10px 1px rgba(0,0,0,0.5);
backdrop-filter: blur(10px);
}