darkSnap/script.user.js

// ==UserScript==
// @name        DarkSnap
// @namespace   http://tampermonkey.net/
// @match       https://snap.berkeley.edu/*
// @exclude     *://snap.berkeley.edu/snap/*
// @icon        https://git.swee.codes/swee/darkSnap/raw/branch/main/DarkSnap.svg
// @grant       none
// @version     4
// @author      Swee
// @description Remix of https://forum.snap.berkeley.edu/t/18272
// @run-at      document-body
// ==/UserScript==
//

document.documentElement.setAttribute('data-bs-theme', 'dark'); // Set dark mode via BS5.
document.documentElement.classList.add("text-white"); // Set the text color with BS5's respective class.
const style = document.createElement('style'); // In case the page doesn't use BS5
style.innerHTML = `
  body, .footer, .body {
    background: #212529 !important;
    color: white;
  }
  .notes, textarea, select {
    background: #2D3142 !important;
  }
  .trapezoid {
    color: #2D3142;
  }
  .trapezoid-footer {
    color: #212529;
  }
`;
document.head.appendChild(style);