Greasy Fork

it works but only on http
to have it working on both http and https, you'll have to change
// @match https://scp-wiki.wikidot.com/*
to
// @match *://scp-wiki.wikidot.com/*

since its that time of the year again, heres a snippet you can add so the script can work without issues on portrait displays (i.e. mobile devices). without this, the logo is a tad oversized and goes behind the title of the page. after line 16, add:
header.style.backgroundSize= "calc(48px + 5%)";
header.style.backgroundPosition= "8px 64%";

if you dont want to set up grease/tamper/violent monkey on mobile to be able to do this, with firefox you can install the Dark Reader addon, and through the developer tools, you can add the following css to section meant for custom scp wiki code
div#header {
background: url("https://scp-wiki.wdfiles.com/local--files/component:theme/logo.png") 10px 40px no-repeat;
background-size: calc(48px + 5%);
background-position: 8px 64%;
}
however if you disable dark mode, the pride logo will return

it works but only on http

to have it working on both http and https, you'll have to change

// @match https://scp-wiki.wikidot.com/*

to

// @match *://scp-wiki.wikidot.com/*

You are not right, script with that match will match even `wss` and `ftp` connections.

P.S. I don't really know if SCP website using wss, ftp and that kind of things