DOM을 건드리지 않고 jQuery를 사용하여 CSS 클래스 규칙을 동적으로 변경하려면 어떻게 해야 합니까?

<code class="javascript">// Get the CSS stylesheet
var styleSheet = document.styleSheets[0];

// Loop through the CSS rules within the stylesheet
for (var i = 0; i < styleSheet.cssRules.length; i++) {
    // Check if the current rule is for the ".classname" class
    if (styleSheet.cssRules[i].selectorText === ".classname") {
        // Set the new font size for the rule
        styleSheet.cssRules[i].style.fontSize = "16px";
    }
}</code>

<code class="javascript">// Build a string containing the updated CSS declarations
var updatedCSS = "";
for (var i = 0; i < styleSheet.cssRules.length; i++) {
    updatedCSS += styleSheet.cssRules[i].selectorText + " {\n";
    for (var j = 0; j < styleSheet.cssRules[i].style.length; j++) {
        updatedCSS += "    " + styleSheet.cssRules[i].style[j] + ": " + styleSheet.cssRules[i].style.getPropertyValue(styleSheet.cssRules[i].style[j]) + ";\n";
    }
    updatedCSS += "}\n";
}

// Send the updated CSS to the server
$.ajax({
    type: "POST",
    url: "/save-css",
    data: { updatedCSS: updatedCSS }
});</code>