Custom style of scollbar in jQuery

I am creating a Chrome Extension using jQuery, however I stuck at style the scrollbar style as
I tried to change .css of this panel element (resultDiv).

- List item

        resultDiv.css({
        "text-align": "left",
        "font-family": "'Segoe UI', sans-serif",
        "font-size": "9.8pt",
        "width": WIDTH_POPUP + "px",
        "max-height": "300px",
        "overflow": "auto",
        //"border": "0.285px solid #ffffff11",
        "padding": "5px",
        "margin": "5px",
        "border-radius": "1rem",
        "color": "#ffffff",
        "background": style_code[value],
        "position": "absolute",
        "top": y,
        "left": currentX + "px",
        "z-index": "99999999999999999",
        "opacity": "0.93"
    });