JSFiddle - React, Tailwind, and code Playground

HTML

<div class="some_selector">Hello</div>
<button onclick="deleteRule('body > div.some_selector')">Remove rule</button>

CSS

body > div.some_selector { 
    font-weight:bold;
    color:red;
}

JavaScript

function deleteRule(selector) {
        // Get the collection of stylesheets and iterate over them
        var ss = document.styleSheets;
        
        // Exit if no stylesheets
        if (!ss.length)
            return;

        // Create an uppercase tagname version of our selector for IE
        var uSelector = selector.replace(/^[a-z]+|\s+[a-z]+/gi, function ($0) {
            return $0.toUpperCase();
        });
        
        // Create a map so we don't get SO's code block scrollbars involved
        var map = {};
        map[selector] = map[uSelector] = 1;
        
        // `deleteRule` for standards, `removeRule` for IE
        var del = "deleteRule" in ss[0] ? "deleteRule" : "removeRule";

        for (var a = 0, maxA = ss.length; a < maxA; a++) {
            // `cssRules` for standards, `rules` for IE
            var rules = ss[a].cssRules || ss[a].rules;

            for (var b = 0, maxB = rules.length; b < maxB; b++) {
                // Check for selector existence in our map
                if (rules[b].selectorText in map)
                    ss[a][del](b);  // remove using our stored delete method
            }
        }
    }