Change images in AtCoder to grayscale with mouse over.
// ==UserScript==
// @name Grayscale AtCoder
// @description Change images in AtCoder to grayscale with mouse over.
// @include https://atcoder.jp/*
// @grant GM_addStyle
// @run-at document-start
// @version 0.0.1.20210628153314
// @namespace https://greasyfork.org/users/788211
// ==/UserScript==
/* jshint esversion: 6 */
GM_addStyle ( `
img:hover {
-webkit-filter: grayscale(100%);
-moz-filter: grayscale(100%);
-ms-filter: grayscale(100%);
-o-filter: grayscale(100%);
filter: grayscale(100%);
}
` );