jisho-dark-mode.user.js

// ==UserScript==
// @name         Jisho Dark Mode
// @namespace    http://tampermonkey.net/
// @version      0.0.6
// @description  Eye friendly dark mode for Jisho.org.
// @author       sheodox
// @match        https://jisho.org/*
// @run-at       document-start
// @grant        none
// ==/UserScript==

(function() {
    'use strict';
    const styleTxt = `
body {
    filter: invert(1);
    background: #24252b !important;
}
header {
    /* weird black background on header */
    background: none !important;
}
/* hide okurigana */
.japanese_word__furigana-invisible {
    color: transparent;
}
.concept_light-tag {
    /* counteract filtering on tags, the background color is fine */
    filter: invert(1);
    /* better contrast text */
    color: black !important;
}
/* wanikani links */
.concept_light-tag a {
    color: black !important;
}
/* make search text stand out better */
#keyword {
    color: black;
    background-color: #cecece;
}
#search_main .inner {
    background: none;
}
/* make grammar breakdowns not super dark */
.fact {
    background: #cecece;
    border: none;
}

/* don't invert context.reviews toasts */
#context-reviews-root {
    filter: invert(1);
}
`;

    const style = document.createElement('style');
    style.textContent = styleTxt;
    document.head.appendChild(style);
})();