Hey there, Anon! It’s okay in my head we’re the bestest of friends and I reciprocate ur puppy eyes don’t even worry bro. This isn’t my code initially, I got it from God knows where haha. The one on my profile is slightly altered so I’ll give you two versions of the code. Modifying the percentages and RGB on the part of the code that says “linear gradient” will change the color and transparency but I don’t recommend changing it too much because I haven’t tested what it’ll do yet lol.

Original Code:

body::before {
content: " ";
display: block;
position: fixed;
top: 0;
left: 0;
bottom: 0;
right: 0;
background: linear-gradient(rgb(0 0 0 / 30%) 50%, rgb(0 0 0 / 0%) 50%);
z-index: 2;
background-size: 100% 2px, 3px 100%;
pointer-events: none;
}

With my Alterations:

body::before {
content: " ";
display: block;
position: fixed;
top: 0;
left: 0;
bottom: 0;
right: 0;
background: linear-gradient(rgb(0 0 0 / 10%) 20%, rgb(0 0 0 / 0%) 80%);
z-index: 2;
background-size: 100% 2px, 3px 100%;
pointer-events: none;
}