index.css

body {
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu", "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

code {
    font-family: source-code-pro, Menlo, Monaco, Consolas, "Courier New", monospace;
}

*::-webkit-scrollbar-track {
    -webkit-box-shadow: inset 0 0 6px rgba(0,0,0,0.3);
    border-radius: 0;
    background-color: #F5F5F5;
    cursor: default;
}

*::-webkit-scrollbar {
    width: 8px;
    background-color: #F5F5F5;
    cursor: default;
}

*::-webkit-scrollbar-thumb {
    border-radius: 0px;
    -webkit-box-shadow: inset 0 0 6px rgba(0,0,0,.3);
    background-color: #555;
    cursor: default;
}