(function flexible(window, document) {
    var docel = document.documentelement;
    var dpr = window.devicepixelratio || 1;

    // adjust body font size
    function setbodyfontsize() {
        if (document.body) {
            document.body.style.fontsize = 12 * dpr + "px";
        } else {
            document.addeventlistener("domcontentloaded", setbodyfontsize);
        }
    }
    setbodyfontsize();

    // set 1rem = viewwidth / 10
    function setremunit() {
        var rem = docel.clientwidth / 24;
        docel.style.fontsize = rem + "px";
    }

    setremunit();

    // reset rem unit on page resize
    window.addeventlistener("resize", setremunit);
    window.addeventlistener("pageshow", function(e) {
        if (e.persisted) {
            setremunit();
        }
    });

    // detect 0.5px supports
    if (dpr >= 2) {
        var fakebody = document.createelement("body");
        var testelement = document.createelement("div");
        testelement.style.border = ".5px solid transparent";
        fakebody.appendchild(testelement);
        docel.appendchild(fakebody);
        if (testelement.offsetheight === 1) {
            docel.classlist.add("hairlines");
        }
        docel.removechild(fakebody);
    }
})(window, document);