<?php
$a = fn($x,$y) => $x*$y;
var_dump($a(3,3));

<?php
$a = (fn($x,$y) => $x*$y)(3,3);
var_dump($a);

<link rel="stylesheet" href="examplestyle.css">

<span id="site_description"></span>

let htmlcode = ["#efefef", "#181B39", "#262a2e", "#192734", "#1c483b", "#bf7800", "#83094f"].map(elm => `<span class='color_code' style='color:${elm}' data-color-code='${elm}'>■</span>`).join("\n");

const basecolor = "#262a2e";
let cookiefn = function (CodeColor) {
    let r = document.cookie.split(';');
    return r.length ? ((r) => {
        let changecolor = "";
        for (let ii = 0; ii < r.length; ii++) {
            let content = r[ii].split('=');
            for (let i = 0; i < content.length; i++) {
                if (content[i].replaceAll(" ", "") === "bgcolor_code") {
                    changecolor = content[i + 1];
                }
            }
        }
        return changecolor?changecolor:CodeColor;
    })(r) : CodeColor;
};

let old_color = cookiefn(basecolor);
document.getElementById("site_description").insertAdjacentHTML("afterend", htmlcode);
[...document.querySelectorAll(".color_code")].forEach(elm => {
    elm.addEventListener("click", function (e) {
        color_set(elm.getAttribute("data-color-code"));
    });
});

color_set(old_color);

function color_set(color) {
    for (let ii = 0; ii < document.styleSheets.length; ii++) {
        if (String(document.styleSheets[ii].href).match(/mag_tcd036-child\/style\.css\?ver=/)) {
            for (let i = 0; i < document.styleSheets[ii].cssRules.length; i++) {
                let element_css_code = document.styleSheets[ii].cssRules[i];
                try {
                    element_css_code.style.backgroundColor = color;
                    if (color === "#efefef") {
                        element_css_code.style.color = "#000000";
                        
                    } else {
                        element_css_code.style.color = "#FFFFFF";
                    }
//いらないかも領域🤔👇
                    document.querySelectorAll("#wp-calendar > tbody > tr > td > a").forEach(elm=>{
                        elm.style.backgroundColor = "#909091";
                    });
                    document.getElementById("searchsubmit").style.backgroundColor = "#000";
                    document.querySelector("#s").style.backgroundColor = "#909091";
                    [...document.querySelectorAll("code")].forEach(elm=>{
                        [...elm.querySelectorAll("span")].forEach(childen_elm=>{
                            childen_elm.style.backgroundColor = "#565656";
                        });
                    });
//いらないかも領域🤔👆                    
                } catch (error) {
                }
            }

            document.cookie = "bgcolor_code=" + color;
        }
    }
}